Two Harvard medical researchers disputed many other witnesses' testimonies in an emotional Senate subcommittee hearing held yesterday and Tuesday on the health hazards of marijuana.

The Criminal Justice subcommittee hearings grew out of the Senate consideration of the Criminal Code Reform Act, which included a provision to decriminalize marijuana.

Dr. Lester Grinspoon, associate professor of psychiatry at the University-affiliated Massachusetts Mental Health Center, said although he does not believe marijuana is safe there has been a lot of misleading or inaccurate research into its detrimental effects. These effects have been exaggerated, he added.

Grinspoon objected to some of the evidence on the grounds that some researchers based their results on tests giving very large doses of THC to animals. These tests with animals produce unreliable results, he said.

Getting Together

Dr. Norman E. Zinberg, associate clinical professor of psychiatry, testified on the possible medical benefits of marijuana.

Zinberg, working with other Harvard researchers, published a study which showed that the active ingredient in marijuana, delta-9-tetra hydrocannibinol, helped reduce nausea and vomiting in chemotherapy.

Sen. Charles M.C. Mathias (RMd.), who led the hearings, said yesterday witnesses had presented definite evidence during the hearing that marijuana was harmful to the brain, the lungs, and the reproductive system.

Counter

He added that he would encourage his colleagues to "reconsider the language" of the decriminalization statement.

There were widespread complaints of harrassment of witnesses by antimarijuana forces outside the hearing and of irregularities in the witness selection process.

Hear No Evil

"People said to me things like 'you ought to be shot' and 'look at what you're doing to our youth,'"

The National Organization for the Reform of Marijuana Laws (NORML) was not invited to testify for the hearings because "the purpose of the hearings was to bring out the medical and biological effects, not to discuss decriminalization," Charlie Borden, a Mathias aide, said yesterday.

Parents and school officials should, therefore, not have been allowed to testify, Alice O'Leary, coordinator of medical and health information for NORML, said yesterday.

Witnesses testifying before the hearing included researchers, psychologists, school officials, and parents.