Defendant appeals his conviction for felony murder committed during a robbery. We reverse.
The state called defendant’s accomplice, Shaw, as its witness. On cross-examination, defendant impeached Shaw by offering evidence of prior inconsistent statements and evidence tending to show that the witness changed his story after entering into a plea agreement (which was referred to in the examination as a “deal”).1 On redirect examination, the state elicited rehabilitation testimony from the witness that, as conditions of the plea agreement, he was required to testify (presumably against defendant), to give the police information about the location of property stolen during the robbery and “to take a polygraph and pass it.”
Defendant’s first assignment is that the court erred by permitting the witness to testify that he had been required to take and pass the polygraph test and by denying defendant’s motion for mistrial after the testimony was given. Defendant states:
“* * * Although the stated purpose of this testimony was to rebut inferences that his testimony was inaccurate or untruthful, the actual use of the testimony was to unfairly infer to the jury that since the test was a part of the plea agreement, he had taken and passed the examination and because he had done this, his trial testimony was above reproach.”
The state argues:
“The defense having painted Shaw as, in effect, a paid liar, the state was entitled to reestablish his credibility by explaining all the factors — including the polygraph condition — contributing to his state of mind. By pointing to the polygraph as another element of the ‘deal,’ the state furnished a convincing explanation for the contrast between the two sets of statements, and thereby rebutted defendant’s claim of fabrication.
“As noted, this is a clear case of the defense ‘opening the door’ to otherwise inadmissible evidence. * * *
*683“There is nothing so special about polygraph evidence that makes it exempt from this [‘opening the door’] rule. In fact, it is no worse than other forms of ordinarily inadmissible evidence which become admissible for purposes of witness rehabilitation, e.g., evidence of other crimes, etc. * * *99
Both parties rely on State v. Green, 271 Or 153, 531 P2d 245 (1975), where the court held that it was impermissible for the prosecution, as part of its showing that a confession was voluntary, to use evidence that the defendant had taken a polygraph test before confessing or evidence of the results of that test. After noting that polygraph evidence is not admissible as substantive evidence in criminal cases, because its reliability has not achieved general scientific acceptance, the court stated:
“[E]vidence of the results of polygraph tests is not admissible as substantive evidence to prove that a person has lied or told the truth. Nevertheless, the jury is likely to infer from evidence of the fact that a criminal defendant was the subject of a polygraph test before making a confession that he lied in response to questions asked during a polygraph test and that he confessed because he was caught lying by the polygraph. As a result, there is danger that such evidence may unduly prejudice the jury in its consideration of the credibility of such a defendant.
“The same is also true, in our opinion, and for the same reasons, of evidence of the results of a polygraph examination and evidence relating to the details of a polygraph examination, from which the jury is even more likely to draw the same inferences.
“For these reasons, it is our opinion that the danger of prejudice from the impact of such evidence upon the question of the credibility of a defendant is so great as to ordinarily outweigh the probative value of such evidence as one or more of the circumstances which the state may properly offer in evidence in laying the initial foundation for the admission of a confession during the trial of a criminal case.” 271 Or at 168-69. (Footnote omitted.)
The question raised by defendant’s first assignment is the permissible scope of rehabilitation of a witness. Defendant makes no issue of the witness’ testimony concerning giving the police information about the location of the stolen property; it is only the polygraph evidence that is *684at issue. More specifically, it is the “passing” of the polygraph examination that is the bone of contention, because “passing” implies truthfulness and therefore bolsters the credibility of the witness. That evidence also does one other, more subtle, thing: it permits the prosecutor to vouch for the witness sub silentio by impliedly saying to the jury, “I have confidence in putting this man on the stand because I have gained independent verification that his story is true.” Next to being allowed to personally take the stand and swear that his witness is truthful, a prosecutor could hardly ask for more.
This is being done under the rubric of rehabilitation after impeachment for bias or interest. The process of impeachment and rehabilitation is governed by OEC 609-1, which provides:
“(1) The credibility of a witness may be attacked by evidence that the witness engaged in conduct or made statements showing bias or interest. However, before this can be done, the statements must be related to the witness and the conduct described, with the circumstances of times, places and persons present, and the witness shall be asked whether the witness made the statments or engaged in such conduct, and, if so, allowed to explain. If the statements are in writing, they shall be shown to the witness.
“(2) If a witness fully admits the facts claimed to show the bias or interest of the witness, additional evidence of that bias or interest shall not be admitted. If the witness denies or does not fully admit the facts claimed to show bias or interest, the party attacking the credibility of the witness may then offer evidence to prove those facts.
“(3) Evidence to support or rehabilitate a witness whose credibility has been attacked by evidence of bias or interest shall be limited to evidence showing a lack of bias or interest.”
The crucial phrase in the rule is in subsection (3): limiting evidence to rehabilitate a witness to evidence “showing a lack of bias or interest.” The evidence proffered by the prosecutor in this case does not show any “lack” of interest or bias: the witness’ interest is manifest. Rather, the proffered evidence is designed to show that, in spite of the interest he admittedly has, this witness is nonetheless telling the truth. The rule excludes such evidence.
*685Assuming arguendo that it did tend to show a lack of bias or interest, rehabilitation evidence of this specific kind, Le., polygraph evidence, would still be inadmissible. Evidence of the results of polygraph tests has been rejected in Oregon, because “the polygraph has not yet attained general scientific acceptance as a reliable and accurate means of ascertaining truth or deception * * State v. Green, 271 Or 153, 165-66, 531 P2d 245 (1975). The state has emphasized this lack of scientific acceptance of the reliability of polygraph tests in successfully convincing us that due process does not require the state to grant an inmate’s request for a polygraph test to be used as evidence in a prison disciplinary proceeding. Sandlin v. OWCC, 28 Or App 519, 522, 559 P2d 1308 (1977). In Green, the Supreme Court held that evidence that the defendant was the subject of a polygraph test before confessing was inadmissible. Applying reasoning parallel to that used by the court in the excerpt from Green quoted above to the facts of this case: A jury is apt to infer from evidence of the fact that a witness was required to take and pass a polygraph test before testifying that he truthfully answered questions asked during the polygraph test and that his testimony before the jury was truthful, because it conformed to what he said during the test. The danger of prejudice from such evidence, on the question of the credibility of a witness is so great as to outweigh its probative value to rehabilitate a witness. Its admission requires reversal.
Defendant’s second assignment is that the court erred in instructing the jury regarding expert testimony. The court instructed that expert opinion should be disregarded if “any of the facts relied upon or assumed by the witness in forming his opinion were not established by the evidence or were untrue.” (Emphasis supplied.) Defendant’s exception to the instruction did not point out that its defect was in its failure to limit consideration to “material” facts.2 We anticipate that the problem will be obviated in a new trial.
*686Reversed and remanded for new trial.
Evidence of the plea agreement was first brought out during the state’s direct examination of the witness. Earlier, defense counsel had referred to the agreement in his opening statement.
The exception defendant took to the instruction, was:
“The exceptions I would take — you gave an instruction regarding the expert opinions, and you indicated that if they found any facts that the person was not aware of to disregard the opinion. I feel the instruction should have *686been to the effect that if they found some facts not present, that they should consider the effect of those misunderstood facts on the opinion.”
The exception does not state that the defect in the instruction was its failure to make the incorrectness of “material facts” rather than “any facts” the criterion for discounting the expert testimony.