dissenting.
¶ 1 I agree with the majority that a medical expert can meet the Frye16 standard in unusual circumstances by extrapolating from generally accepted theories.17 However, in this case, the trial judge at no point conducted a Frye hearing, and from the record we cannot determine whether Dr. Shane’s testimony did or did not meet the Frye standard. Therefore, I would remand for a full Frye hearing. If it is determined that the Frye standard was met, there would be no need for a new trial. If the Frye standard was not met, then there should be a new trial.18
¶ 2 Frye itself supports the premise that an expert can make an extrapolation from well-recognized scientific principles. In Frye the court said:
Just when a scientific principle or discovery crosses the line between the experimental and demonstrable stages is difficult to define. Somewhere in this twilight zone the evidential force of the principle must be recognized, and while courts will go a long way in admitting expert testimony deduced from a well-recognized scientific principle or discov*1121ery, the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs.
293 F. at 1014.
¶ 3 The statement that “courts will go a long way in admitting expert testimony deduced from a well-recognized scientific principle” supports extrapolation, so long as “the thing from which the deduction is made [is] sufficiently established to have gained general acceptance.” Id.
¶ 4 The procedures conducted by the trial judge in the instant case had the result that neither side was given the opportunity to put on the kind of testimony that would enable one to determine whether Dr. Shane’s opinion is or is not based on generally accepted underlying principles. The trial judge first ruled on a motion in limine without healing, ruling that the Frye standard was met and allowing Dr. Shane to testify. Then, on post-verdict motions, again without any Frye hearing and without any evidence being taken, the judge held that Dr. Shane’s testimony did not meet the Frye standard.
¶ 5 Although Dr. Shane’s extrapolations seem reasonable, the record is not clear enough to demonstrate that the underlying basis upon which Dr. Shane relies for his extrapolation meets the Frye standard. At the motion in limine stage, without a hearing, the defense was unable to challenge the underlying basis of the literature on which Dr. Shane relied to say that the drug Doxepin caused pigmentary or “open-angle” glaucoma. At the post-verdict motion stage, without a hearing the plaintiff was unable to refer to the literature that would support his extrapolations. When Dr. Shane did refer to literature in the course of the trial, the references were precluded because under Pennsylvania law, textbooks are hearsay, not subject to any exception.
¶ 6 Therefore, I would remand the case to the trial court to conduct a full Frye hearing. If Dr. Shane’s testimony passes Frye muster, there is no need for a new trial. If it does not pass Frye muster, then a new trial would be in order.
¶ 7 Since the dosage administered to Mr. Trach of the anti-depressant drug Doxepin was far in excess of the recommended dosage, and prescription of the drug had been generally discontinued (R.R. 339a, N.T. 6/16/99, p 185, 196), there were not and will not be any significant studies dealing with humans receiving this massive overdose. (R.R. 385a, N.T. 6/16/99 p. 243-44).
¶ 8 As I view Frye, the basic issue in this case is whether Dr. Shane’s testimony that Doxepin caused Mr. Trach permanent injury is sufficiently reliable to be admitted to the jury. As noted by the majority, other jurisdictions have permitted expert witnesses to extrapolate based on generally recognized medical principles. There is no reason why we cannot use this approach in Pennsylvania.
¶ 9 To boil the testimony down to its elements, glaucoma is caused when pressure builds up in the eye. This occurs when the fluid in the eye is not drained through the Canal of Schlemm. The defense experts said that the side effects from Doxepin only cause “closed-angle” glaucoma, when the entry to the Canal of Schlemm is narrowed and for this reason pressure builds up in the eye. According to the defense, the type of glaucoma suffered by Mr. Trach is “open-angle” or pigmentary glaucoma, which essentially results when pigment is lost from the iris and blocks up the filter system of the Canal of Schlemm.
¶ 10 Dr. Shane testified as to the massive overdose of Doxepin that Mr. Trach received. He testified that in addition to *1122the closed-angle compression of the Canal of Schlemm, there would be pigmentary loss from the excessive dilation of the pupil of the eye, which would clog the filter of the Canal of Schlemm causing the pressure to build. That would result in the kind of permanent glaucoma from which Mr. Traeh suffers. (R.R. 340a, 347a, 349a, 367a; N.T. 6/16/99. pp. 198, 205, 207, 225.) This is an extrapolation by Dr. Shane, since with therapeutic doses of Doxepin, the result is usually closed-angle glaucoma.
¶ 11 The extrapolation makes sense if and only if Dr. Shane’s basic premise is correct, that is, that Doxepin causes loss of pigment. When asked about this, Dr. Shane referred to several textbooks. However, since his testimony had already been ruled admissible, these background texts were inadmissible as hearsay under the Pennsylvania Rules of Evidence.19
¶ 12 Dr. Shane attempted to minimize the distinction between open-angle and closed-angle glaucoma, but when he referred to the published literature, using New York Eye and Ear as an example, the defense raised an objection and the trial judge ruled that such literature is inadmissible hearsay in Pennsylvania state courts. (R.R. 347a-349a, 366a; N.T. 6/16/99, pp. 205-207, 224). When the defense challenged Dr. Shane, saying that there is nothing in the literature to support his opinion, Dr. Shane replied that the results were in the literature although why Doxepin causes these results was unknown. The testimony (R.R. 362a-363a, N.T. 9/16/99 pp. 220-221) reads as follows:
Q. But there’s nothing in the medical literature which states the opinion that you’re giving here in the courtroom today. Is there, sir?
A. [By Dr. Shane] Oh, absolutely. Every opinion I have given today is supported very definitely in the medical lit- ■ erature. It’s supported in things that are available on every physician’s desk like the Physician’s Desk Reference. It’s supported in the medical literature by the textbook on toxicology written by Randall Bassault. It’s supported by other textbooks — Ellenhorn will support what I have said. I said nothing today to this jury that isn’t supported by medical literature.
What’s not in the medical literature is how does it block the distal end of the synapse? We don’t know. And we don’t have a lot of history on massive overdoses because the drug has been out of favor sufficiently long that folks have not overdosed. It has not been a popular — it has not been an available or popular street drug.
¶ 13 At trial, the defense did not explore the contents of the literature. Therefore, because the literature was not presented by either side at trial, the record neither supports nor contradicts the bases of Dr. Shane’s opinion. It is improper to rule that his opinions should be discarded under Frye when the trial court never explored the literature to see whether or not there is a basis for his extrapolation from the results found from therapeutic doses of Doxepin.
¶ 14 Likewise, the defense did not have the opportunity to explore the literature to challenge the bases of Dr. Shane’s opinion at a post-verdict hearing. There was no hearing at the motion in limine, the literature was not at issue during trial, and there was no hearing at the post-verdict stage where the literature could be evaluated to examine this underlying premise.
*1123¶ 15 The majority takes the position that by failing to challenge Dr. Shane’s claim that the literature supported his theories during trial, the defense has conceded that the literature does in fact exist and supports Dr. Shane’s opinion. However, the majority overlooks the fact that it might not have been strategically wise for the defense to explore the literature at trial. By the time Dr. Shane testified at trial, the defense had already lost the Frye issue at the motion in limine stage. During trial, the defense had to be concerned about winning the case, not about establishing a record to challenge the ruling on the motion in limine. In a major malpractice case, lawyers would legitimately not want to focus on a detailed challenge of the literature to distract the jury from other points they make on cross-examination. Having already lost the Frye issue, it is unfair to hold the defense conceded this point simply because they did not put in enough evidence at trial to support their Frye arguments. The time to establish a record is at a Frye hearing, outside the presence of the jury. If this does not take place on a motion in limine, it should take place before a ruling on post-verdict motions. The problem in this case (both for us as an appellate court and for the parties) is that neither side ever had the proper opportunity to develop a record to support their position on Frye.
¶ 16 Therefore, we as an appellate court cannot determine whether or not the basic premise upon which Dr. Shane extrapolated to reach his conclusion is generally accepted science. If it is, then the extrapolation is justified. If it is not, then the extrapolation fails because the basis of the extrapolation is not supported.
¶ 17 We have made the interpretation of the Frye principle far too complex. We should be able to come up with a commonsense approach to the “gatekeeper” function of the trial court when it comes to scientific evidence.
¶ 18 I believe we can conduct this analysis by following four simple principles.
1. Frye applies to scientific testimony whenever there is a legitimate dispute as to whether the expert’s conclusions or methodology are generally accepted.
2. If the expert’s conclusion is generally accepted, then there is no need to evaluate his or her methodology.
3. If the expert’s conclusion is not generally accepted, then courts must determine whether the underlying methodology is rehable.
4. The challenger bears the burdens of production and proof. The trial court should deny the motion without a hearing unless the movant has presented and supported a prima facie case that the evidence is not generally accepted.
A detailed analysis follows.
1. Frye applies to scientific testimony whenever there is a legitimate dispute as to whether the expert’s conclusions or methodology are generally accepted.
¶ 19 Pennsylvania law often states that the Frye standard applies to “novel” science. See, e.g., Pa.R.C.P. 207.1, Explanatory Comment — 2001. As noted in the majority’s opinion, “novel” does not necessarily mean “new.” A careful consideration of the purpose of the Frye rationale shows that the Courts are referring to the second meaning of “novel,” not the first. While the term “novel” can mean “new;” it can also mean “having no precedent” or “unusual.”20
*1124¶ 20 The majority states that the evidence must “in some sense” be novel. Id. Our Supreme Court’s decision in Blum does not address whether Frye applies only to novel science, and therefore does not concern itself with a definition of “novel.” The Supreme Court’s opinion dealt with whether Daubert or Frye controlled, and for that reason the majority of the Supreme Court did not address that question. Only the dissenters raised it, which obviously does not end our inquiry. Nor have I found any other controlling precedent.
¶ 21 As Judge Beck noted in Blum by Blum v. Merrell Dow Pharmaceuticals, Inc., 705 A.2d 1314, 1317 (Pa.Super.1997), aff'd, 564 Pa. 3, 764 A.2d 1 (2001), Frye is designed to ascertain whether the scientific evidence is of sufficient reliability to be presented to the jury. Judge Beck said:
The Frye test represents an attempt to measure the quality of scientific evidence prior to admission, so that jurors are not misled by unreliable evidence. Our courts have considered this to be necessary whenever science enters the courtroom because “there is the danger that the trial judge or jury will ascribe a degree of certainty to the testimony of the expert ... which may not be deserved.”
705 A.2d at 1317 (quoting Commonwealth v. Topa, 471 Pa. 223, 369 A.2d 1277, 1281 (1977)).
¶ 22 Just as “novel” is a confusing term, it is. also confusing to say that Frye applies “whenever science enters the courtroom.” The better way to phrase it is to say that Frye applies whenever a party claims that an opposing expert’s theory and/or methodology is not generally accepted. The methodology need not be “new” or involve cutting-edge technology. Such a definition of “novel” would be unreasonably narrow. For example, lie detector tests have been in existence for many years, and are certainly not “novel” in the sense of being new or “cutting-edge.” Yet even today this technology is still not generally accepted in the scientific community. Moreover, a temporal or technological view of “novelty” would unreasonably hamper'the trial judge’s gate-keeping function to ensure that all scientific methodology is generally accepted before it is presented to the jury.
¶ 23 At the same time, a broad reading of the phrase that Frye applies “whenever science enters the courtroom” may conjure up a vision of Frye hearings in every case. That also is not true. One should not confuse the issue of the standard to determine admissibility and the issue of whether the trial court should hold a Frye hearing. Sometimes the expert’s opinion is clearly accepted by the scientific community and there is no challenge, and therefore no hearing will occur. For example, no one would ask for a Frye hearing if an expert would testify that antibiotics are helpful in treating infections. An example in this case is the opinion that if pressure builds in the eye, glaucoma may result. Although theoretically Frye could apply to all testimony from every scientific expert, in most cases the opponent will raise no challenge. For general medical testimony that is widely accepted, no responsible lawyer would ask for a Frye hearing and irresponsible lawyers would be sanctioned. Also, if the petition and answer show that there is no real question that the expert’s opinion or methodology is generally accepted, the matter can be decided without a hearing on a standard akin to summary judgments.
¶ 24 While I would hope that in the future we would use a term other than “novel” when talking about when Frye applies, if “novel” is defined as “having no precedent or unusual,” this fits with the *1125law as it has developed. I believe that the proper standard, which I think is adopted by the majority, is that Frye properly governs the admissibility of expert testimony, new or old; whether there is a legitimate dispute as to whether it is generally accepted. If that is the case, then the trial court will need hear a challenge and probably hold a hearing. But the need for a Frye determination will be relatively rare.
2. If the expert’s conclusion is generally accepted, then there is no need to evaluate his or her methodology.
¶ 25 As for how the court should conduct the inquiry, I propose a sensible two-step approach. The first step would be to determine whether the conclusion is generally accepted, as discussed above. Some conclusions (including some relating to causation) are generally accepted: e.g., botulism causes certain symptoms. If the general acceptance of the conclusion can be established, why should courts delve into methods? Once the theory of causation has been admitted by the court above as generally accepted, that will usually be the end of the inquiry and the evidence will be admitted.
¶ 26 However, where there is a claim that the body of opinion has changed, or has become uncertain, the opponent needs an opportunity to prevent the expert’s testimony from going to the jury unless it has a reasonable basis. In such a situation, the trial court should conduct a hearing to determine admissibility using Frye standards.
3. If the expert’s conclusion is not generally accepted, then courts must determine whether the underlying methodology is reliable.
¶27 When the expert’s opinion is not considered generally accepted, then courts must move to a second step. The second step would focus on the underlying methodology. This step would arise where the expert’s conclusion has not reached general acceptance, but the testimony is based on generally accepted procedures. As the New Jersey Supreme Court phrased it, “[A] theory of causation that has not yet reached general acceptance may be found to be sufficiently rehable if it is based on a sound, adequately-founded scientific methodology involving data and information of the type reasonably relied on by experts in the scientific field.” Landrigan v. Celotex Corp., 127 N.J. 404, 605 A.2d 1079, 1084 (1992) (quoting Rubanick v. Witco Chem. Corp., 125 N.J. 421, 593 A.2d 733, 747-48 (1991)).
¶ 28 When the opinion of the expert is not generally accepted, the trial court should hold a hearing to examine the methodology, data and information. The court should examine the basis of the methods, and whether the data was the sort that experts in the field reasonably use. If so, the opinion should be admitted.
¶ 29 Both the conclusion and the methodology may be important, but at different points in the analysis.
4.The challenger bears the burdens of production and proof. The trial court should deny the motion without a hearing unless the mov-ant has presented and supported a prima facie case that the evidence is not generally accepted.
¶ 30 These substantive legal principles have a significant impact on the procedural issue of when and how Frye hearings should be conducted. First, the party seeking to bar evidence under Frye must identify precisely what is arguably not generally accepted about the expert’s opinion. See, Pa.R.Civ.P. 207.1(a)(1). More*1126over, the following principles would apply to the Frye motion.
¶ 31 If the moving party concedes that the expert’s conclusion is generally accepted, the inquiry would end. The trial court would deny the motion and allow the expert to testify. Similarly, if the moving party argues that the expert’s conclusion is not generally accepted, but concedes that the methodology is generally accepted, the inquiry would end. The trial court would deny the motion and allow the expert to testify. As the Majority cogently explains, if the expert used established, accepted scientific methods to come to a newly-recognized conclusion, the opinion should not be excluded under Frye. The matter is left for the jury to resolve.
¶ 32 Thus, the party seeking to exclude evidence under Frye has the initial burden of presenting a prima facie case that the expert’s conclusion and methodology have not been generally accepted. Upon receiving such a motion, the trial court has two options:
1. The court could rule on the pleadings that either the expert’s conclusion or methodology is generally accepted. In such a situation, the court would deny the motion and allow the expert to testify. See, Majority Opinion at 1110 (“general acceptance” standard can be incorporated into the concept of judicial notice). Because trial courts retain the power to summarily reject requests for Frye hearings, there is no danger of our trial courts being flooded with Frye requests every single time that “science enters the courtroom.”
2. The trial court could hold a Frye hearing. After the hearing, if the court determines that the expert’s conclusion is indeed generally accepted, the court would allow the expert to testify. (It may often be the case that a trial court does not know if a conclusion is generally accepted until the court takes evidence on this issue.) If the court finds that the conclusion is not generally accepted, that finding would not end the inquiry. Rather, the court would then proceed to determine if the expert’s methodology is generally accepted. If so, the court would allow the expert to testify. If not, the testimony would be barred under Frye.
¶ 33 In any event, trial courts are to comply with Pa.R.Civ.P. 207.1, which provides that, where a party files a Frye motion with the trial court, the court, in its discretion, can hold a Frye hearing before trial or defer it to trial.21 Pa.R.C.P. 207.1(a)(3). Where a party does not raise the issue of the admissibility of the testimony of an expert witness prior to trial, and is not ordered by the trial court to do so, nothing in the Rule precludes raising the issue during trial. See, generally, Rule 207.1(b).
‡ ‡
¶ 34 In this case, I do not believe that it is generally accepted that Doxepin causes pigmentary or open-angle glaucoma. However, I agree with the majority that it is possible that Dr. Shane’s extrapolation from the theory that Doxepin causes a flaking of the eye’s pigment can be extended to find that under such a massive over*1127dose, the pigment can obstruct the flow into the Canal of Schlemm. I do not believe the procedure followed by the trial court enables us to determine whether Dr. Shane’s extrapolation is based on generally accepted medical theory. Since there never was a Frye hearing, the record is unclear whether there is general acceptance that Doxepin causes any flaking of the pigment.
¶ 35 Here, when the defense questioned the admissibility of Dr. Shane’s testimony pre-trial, the trial court denied the motion in limine without a hearing. When Dr. Shane referred to his supporting literature in his trial testimony, this body of literature was excluded for the reason that in Pennsylvania, learned treatises are hearsay. When defendants re-raised the issue in post-trial motions, the trial court granted the motion based on the trial testimony without holding a specific Frye hearing, which could have explored the literature. I believe the testimony at trial was insufficient to support admission of Dr. Shane’s conclusion that in this case Doxepin caused permanent loss of vision (and some cognitive functions) because of the failure to support Dr. Shane’s statement that even therapeutic doses of Doxepin cause flaking of the pigment. However, Trach was not triggered to put on more definitive evidence because the motion in limine had already been denied.
¶ 36 The trial court should have held a Frye hearing, preferably at the motion in limine stage, or at least before reversing the jury’s decision on the basis of Frye. If that had been done, then the record would have been fully developed. Trach would have had the opportunity to establish the general acceptance of the basis of Dr. Shane’s expert’s opinion,22 and the defense would have had the ability to challenge the underlying theory upon which Dr. Shane relied for his extrapolation. In nearly every case in which a Frye challenge is raised, a hearing will be needed to assess whether the opinion is generally accepted. Failure to hold a hearing will often result in error, as it did in this case.
¶ 37 I would therefore vacate the trial court’s decision and remand for an opportunity for the parties to follow the procedures outlined above, with the trial court giving both sides the opportunity to present evidence, if desired, and to make further argument following the presentation of evidence.
. Frye v. United States, 293 F. 1013 (D.C.Cir.1923).
. I also agree that the Frye objection was properly preserved in the motion in limine.
.A new trial would be necessary because judgment n.o.v. should not be entered on a diminished record. Jones v. Treegoob, 433 Pa. 225, 249 A.2d 352 (1969); Hughes v. John Hanna & Sons, 187 Pa.Super. 466, 144 A.2d 617 (1958).
. See Pa.R.E. 803, comment to Section (18), Learned Treatises (noting that Pennsylvania has not adopted the federal hearsay exception for learned treatises).
. Webster’s Third New International Dictio- nary (1966).
. The wisdom of Rule 207.1, limiting the timing of Frye hearings, is apparent in the instant case. Here, the trial court summarily reversed itself after trial without taking any evidence on the issue. In doing so, our review of the matter has been significantly hampered.
. The failure to hold a hearing is contained within Trach’s argument that the trial court misapplied Frye.