Re: I guess this is it...

Constipation can occur from many sources such as magnesium deficiency, potassium deficiency, lack of fiber, dysbiosis caused by a lack of probiotics and short chain fatty acids.

If you think you are harboring roundworm, I would confirm by doing a google images search.

I never any success with the Black-Walnut type of cleanser but got them out using enteric coated oil of oregano, neem, boswellia and myrrh. Worked just fine in about 1 week.