The psychological benefits include anxiety reduction, sedation, and euphoria can influence their potential therapeutic value
But the institute also noted that smoking marijuana is a "crude" method that delivers harmful substance.
After their children left home, the Kahns left the United States to live in Israel, where their younger son was serving in the combat military and where medical marijuana is used legally and "robustly," he said.
Stephanie Kahn's father had been ill with multiple sclerosis for 50 years.
"In the 1970s he was going from doctor to doctor to try to find relief and couldn't find anything until someone suggested he try marijuana," said Kahn. "It gave him significant relief."
But the man never lived to get marijuana "safely and legally," according to Kahn.
In 2009, the couple came home to the U.S. because of transitions in their family --- they were to become grandparents and Stephanie Kahn's mother fell ill with lung cancer.
They settled in Washington, D.C., where their older son lived.
"She was going through very aggressive chemotherapy and radiation and her doctor in New Jersey had recommended medical marijuana, but she wasn't able to find it," he said. "She wasted away and lost 40 pounds in a few months."
Ending suffering trumps all other Jewish laws, according to Kahn. A sick patient is not expected to fast on Yom Kippur; Jews have a responsibility to help the sick even when they are supposed to be praying.
"God would never forbid the need to go to a hospital," Kahn said. "We put people in the ambulance and treat them with all the medical equipment -- even the orthodox do."
In addition to marijuana, which the Kahns obtain from 10 warehouses around the District of Columbia, the dispensary provides a large selection of equipment, including a "magical butter machine" that converts the drug to butter, oil or tinctures.
But Kahn also finds more traditional ways to bring comfort to his patients.
"I find so much of my time is spent counseling people and speaking to people on the phone," he said. "I can't say that everybody facing illness likes to have someone to talk to. But lots of people do and I am using my rabbinical skills -- and that's really great."