Cycus circinalis L. (Cc) and Ionidium suffruticosum Ging., (Is) were used in Siddha system of medicine (Indian Medicine) for years together to improve the fertility of male. Both the herbs have aphrodisiac activity. The study was carried out to evaluate the acute toxic effect of the ethanolic extract of both the herbs Cc and Is and to determine the LD<inf>50</inf>. The acute toxicity study (Main test) was done as per the guide lines of Organization for Economic Cooperation and Development (OECD) guideline 425. As the herbs were used for treating male infertility by traditional practitioners for years together, the toxicity study was also proposed to study in male albino rats. About 18 male albino rats of three groups having six rats in each group of Control, Experimental I and Experimental II. The ethanolic extracts of Cc and Is were administered by oral gavage. The distilled water was administered to control rats, Cycus circinalis extract for Experimental I and Ionidium suffruticosum extracts for Experimental II in single dosages of 175, 550, and 2000mg/kg bodyweight with 48hrs of interval between the dosages as recommended in OECD guidelines 425. The weight of rats, Wellness parameters, mortality, hematological parameters, biochemical markers, and histopathological analysis of all vital organs were observed to know the acute toxic effect of the drugs Cc and Is. All the parameters of the study do not show any significant changes between the control and experimental groups. There was no mortality among the experimental groups. The high no- observed adverse effects level (NOAEL) value of 2000 mg/kg bodyweight implies that the drug could be safe and the LD<inf>50</inf> value of both Cc and Is was found to be more than 2000 mg/kg bodyweight by this acute toxicity study. © 2013 Elsevier B.V., All rights reserved.