Conditions have been worked out for a reliable estimation of the cataleptic activity of delta'-trans-tetrahydrocannabinol (THC) after oral administration to mice, using the ring test over a period of 6 h. By this method, the activity of cannabis herb and 5 crude fractions were measured against THC; at the same time the THC contents were determined chemically. The B/C ratio (biological activity divided by chemical assay) was calculated for each. With cannabis herb the value was 3.3 and with extracts prepared with ethanol or 70% ethanol the values ranged from 3.2 to 7.1, indicating that in all samples the activity was much higher than...

Background and Objectives: D9‐tetrahydrocannabinol (THC) promotes sleep in animals; clinical use of THC is associated with somnolence. Human laboratory studies of oral THC have not shown consistent effects on sleep. We prospectively evaluated self‐reported sleep parameters during controlled oral THC administration to research volunteers. Methods: Thirteen male chronic daily cannabis smokers (mean SD age 24.6 +/- 3.7 years, self‐reported smoking frequency of 5.5 +/- 5.9 (range 1–24) joint‐equivalents daily at study entry) were administered oral THC doses (20 mg) around‐the‐clock for 7 days (40–120 mg daily) starting the afternoon after admission. The St. Mary’s Hospital Sleep Questionnaire was completed every morning. Plasma THC and...