Simpson Oils alternative oil treatment for Cancer's in advanced stages There are many advantages to the rectal administration of cannabis oil not afforded by other routes. Once inserted, the capsule dissolves and is absorbed into the bloodstream through the thin lining of the intestinal wall. Simpson Oil rectal cannabis suppositories are incredibly bioavailable, meaning they’re easy for the body to use. Unlike other forms of medical cannabis, rectal suppositories do not make users euphoric. Generally these treatments are administered just prior to sleep so your mind will still feel clear and sharp during the day. The effects of rectal cannabis can last up to eight hours without re-administration.