Interesting that you should ask that. Just recently Rabbi Chaim Kanievsky, who is widely considered to be the leading ultra-orthodox rabbi in the world, ruled that medical cannabis can be eaten or smoked over the 10 day Passover celebration.
Normally cannabis leaves are considered part of a legumes or grains that are banned for Jews of Ashkenazi origin. Observant Jews don’t eat leavened grain products during the eight days of Passover because the holiday commemorates the Biblical story of Exodus, when Jews fleeing slavery in Egypt didn’t have time to let their bread rise. They took instead flat, hard unleavened bread that today is sold as matzo. Passover dietary rules forbid consumption of certain grain-based foods like bread and pasta that puffs up when cooked.
Perry Solomon, MD