The effect is stronger against Gram-positive than Gram-negative bacteria and against DNA than RNA viruses; it is suppressed by serum and by sulfur compounds such as hydrogen sulfide, mercaptoacetic acid, cystine and glutathione.[3][5][6][7][8] The antibacterial, antifungal and antiviral effects from consuming radishes were recognized in traditional Chinese medicine.[9] However, in the abstract to his 1947 paper, Ivanovics noted that because raphanin is highly toxic, it did not "hold the promise of a useful therapeutic agent".[10]