This appeal presents two evidentiary questions which arose during defendant’s trial for possession of a controlled sub*621stance. We reverse on one; and since we remand for further proceedings, we resolve the other for the guidance of the trial court and counsel in the event of another trial.
The information charged defendant with possession of a controlled substance with intent to deliver. § 204.401(1), The Code. The contraband in question consisted of 46 LSD tablets.
I. Defendant claims it was error to permit a police officer to testify the amount of LSD in defendant’s possession at the time of his arrest “far exceeds what one might possess for personal use.”
We have faced similar problems in various forms several times in the past several years. The rule developed from these cases is that a properly qualified witness may testify to the customs and practices of those who use or deal in narcotics. State v. Boyd, 224 N.W.2d 609, 613 (Iowa 1974). From these circumstances and any other evidence produced, the jury must find whether the drug is held for personal use or for delivery. This determination is not to be made by a witness, no matter how expert he is. State v. Oppedal, 232 N.W.2d 517, 524 (Iowa 1975); State v. Horton, 231 N.W.2d 36, 38 (Iowa 1975).
In the present case, Officer Zimmerman was asked to state whether the quantity defendant possessed would be “more or less than that which would be considered for personal use.” Over proper objection, he was allowed to give his opinion and stated:
“In my opinion, 46 tablets of LSD far exceeds what one might possess for personal use.”
Although phrased a little differently, the effect of this statement was identical to the objectionable answers in Oppedal and Horton. Ordinarily possession of drugs is either for personal use or for delivery to others. Quite obviously Officer Zimmerman’s answer was intended to convey the idea defendant was guilty of the latter rather than the former. This was the indisputable impact of that testimony, and it is precisely the vice condemned in Oppedal and Horton. It also violates the rule we have firmly adhered to since Grismore v. Consolidated Products Company, 232 Iowa 328, 361, 5 N.W.2d 646, 663 (1942), (and have recently reiterated in Oppedal), where we said:
“No witness should be permitted to give his opinion directly that, a person is guilty or innocent, or is criminally responsible or irresponsible * * * ”
This case bears some similarity to State v. Droste, 232 N.W.2d 483, 488 (Iowa 1975). In Droste we held it was error to. permit a witness to say the results of a breath test exceeded the alcohol limit allowed by § 321.281. We said this:
“When a standard, or a measure, or a capacity has been fixed by law, no witness, whether expert or non-expert, nor however qualified, is permitted to express an opinion as to whether or not the person or the conduct, in question, measures up to that standard. On that question the court must instruct the jury as to the law, and the jury must draw its own conclusion from the evidence.”
In the case now before us there is no specific statutory standard. However, the section fixes a general test based on intent to determine which degree of an offense defendant is guilty of. The rationale of Droste is even more persuasive where the criterion to be applied is such a subjective one as defendant’s intent.
We hold Officer Zimmerman here was improperly permitted to express an outright opinion as to defendant’s guilt on one of the essential elements of the crime.
The case must be reversed for that reason.
II. Defendant’s second complaint is based upon the trial court’s ruling allowing the same officer to express his opinion concerning the effects of LSD. Defendant argues the witness was not a chemist nor was he shown to be otherwise qualified to give his opinion on this matter.
The admission or rejection of expert testimony is largely a matter of trial court discretion. We will not interfere absent manifest abuse. State v. Martin, 217 *622N.W.2d 536, 545-546 (1974); Ganrud v. Smith, 206 N.W.2d 311, 314-316 (Iowa 1973). In Martin the proffered evidence of the effects of LSD was rejected. In Gan-rud evidence by a non-medical witness concerning retrograde amnesia was allowed. In each case we affirmed, finding no abuse of discretion in either ruling. See also Rigby v. Eastman, 217 N.W.2d 604, 608 (Iowa 1974).
We detail Officer Zimmerman’s qualifications to express an opinion on the effects of using LSD. He had been a narcotics officer for three years. He graduated from Des Moines Area Community College and received two degrees, one in law enforcement and one in criminalistics. He took college courses in psychology, social issues, and toxicology and narcotics. The last course covered all drugs and their elements, including their effects on the human body. He attended a school sponsored by the National Training Institute and the Department of Drug Enforcement at Washington, D. C. for a two week period. Part of this course dealt with the characteristics of LSD. He had read a number of books on drugs and received a monthly fact sheet on drugs, including LSD, from the National Training Institute. He had participated in a number of drug raids where LSD was seized. He had made 15 or 20 street purchases of LSD as an undercover agent. He had talked about the drug with approximately 200 users over a period of time.
Although he has had no training as a chemist, he testified he has had training in recognizing and identifying LSD.
After the above facts were shown, the witness was allowed to say, over proper objection, that LSD is a hallucinogenic, mind-altering drug. He was also allowed to say that LSD has a short shelf life and quickly deteriorates.
We hold Officer Zimmerman’s qualifications outlined above warranted the admission of this testimony. We find no abuse of discretion in the trial court’s ruling.
III. For the reasons stated in Division I, the judgment is reversed and the case is remanded for a new trial.
REVERSED AND REMANDED FOR NEW TRIAL.
MASON, RAWLINGS, REES and REYNOLDSON, JJ., concur. UHLENHOPP, J., MOORE, C. J., and HARRIS and MeCORMICK, JJ., dissent.