I had bought Maracyn, and in their pamphlet they list symptoms and which one to use. They list Maracyn II for internal parasites. Also Dr Foster and Smith have it listed in the internal parasite section. It worked for me, I had tried clout and another generic brand, they didn't do the job. After the first dose they still had the stringy feces, so I did a 50% water change and tried it again. By the fourth day their feces was getting color and their stomach wasn't getting bloated any more.