Absorption of mebendazole is strictly in the intestinal tract and it is not systemic. Absorption rate is about 5%. It is a very tough drug on your intestinal lining. Low dose for a long period brings better results, like max 100-200-300 mg max p day. Need to take w food, and with fat. Should you experience pain or GI discomfort more than usual, you will know it is the mebendazole. I think albendazole works much better. 200-400mg max p day. If your worms are nocturnal, best to take the meds evening or late night.