Experimental evidence exists to indicate that retinoids may act as detergents to disrupt biological membranes. Taurine, an amino sulfonic acid, has been shown to possess membrane-stabilizing and cytoprotective properties. This study was undertaken to test whether taurine coadministered with isotretinoin might be able to protect against the teratogenic effects of the retinoid. Our study failed to find any support for this speculation. Whether challenged against a 75 (mildly teratogenic) or 150 (very teratogenic) mg/kg/day dose of isotretinoin, taurine for the most part worsened the retinoid embryotoxicity. While in a few combinations taurine decreased the resorption or malformation rate associated with isotretinoin, the decrease was, at best, marginal. In no case was taurine able to decrease these rates to those noted in the controls.