1. Daily administration of cannabis extract (12.5 mg/kg body wt. for 30 days) produced a complete arrest of spermatogenesis in dogs. Distinct degenerative effects were produced in the form of extensive fibrosis and exfoliation of the seminiferous elements. 2. RNA, protein and sialic acid contents of the testis and epididymides were reduced after cannabis extract administration, whereas, testicular cholesterol and enzyme phosphatase were elevated. 3. Serum transaminases were slightly elevated, whereas the alkaline phosphatase and haemoglobin/haematocrit values were in normal range. 4. Histophysiological examination of the liver did not show any damage. 5. Reduced androgen production was reflected in low levels of sialic acid in the testis and epididymides, and shrunken Leydig cell nuclei and luminal epididymal epithelium. 6.
In conclusion: Cannabis extract at 12.5 mg/kg body wt. dose level did not cause severe damage to the vital organs but it produced an effective inhibition of spermatogenesis in male dogs in 30 days and thus induces an antifertility state. The possibility of an adverse effect of frequent marihuana use on male reproductive organ functioning in man is alarming.