Several over-the-counter drugs are offered to patients,and they do not have information on the side effects due to their frequent consumption. This stimulated us to evaluate the antitoxicological effect of potato tocosh (Solanum tuberosum) compared to sulfamethoxasol-trimethopin in onion roots (Allium cepa). Rootlets of 3.0 cm were developed in 20 onion bulbs, which were sustained in four procedures: control (100 ml of distilled water), problem 1 (20 uL of tocosh), problem 2 (sulfamethoxasol-trimethoxasol 1%) and problem 3 (sulfamethoxasol-trimethopine 1% plus20 uL of tocosh.). The Tjio and Levan staining technique was applied for cellular observation. Group 3 presented: clastogenic chromosomal anomalies: bridges (2.3%), multiple bridges (1.2%), chromosome in c-metaphase (0.5%) and aneugenic: sticky chromosome(1.1%) and yolk nuclear (1.3%) and without aberrations (99.6%) while the group that received antibiotic plus tocosh expressed a lack of chromosomal abnormalities. Under laboratory conditions, at a dose of 2uL of tocosh, the best antitoxicological effect was perceived in roots of Allium cepa which shows tocosh as an antitoxicological alternative to the toxic power of certain drugs.