Why would the homeopathic remedy Arsenicum 6c discourage a cockroach invasion? First lets look at the remedy picture, it is for those who are overly fussy, tidy and organized. They constantly clean things and sort things out. These behaviors were commonly found in the homeopathic proving trials for Arsenicum. Homeopathy works according to the Law of Similars (like treats like) and people are reporting that it really works to keep cockroaches away.