BACKGROUND Salvia miltiorrhiza Bunge named Danshen in China has been used for hundreds of years in both China and other countries. Danshen injection made from the aqueous extract of Danshen which is widely adopted in China is one of the traditional Chinese medicine injections for preventing and treating cardiovascular diseases in most of the time. The present study was carried out on re-evaluating the safety of Danshen injection by determining toxicity after acute and sub-chronic administration in Sprague-Dawley (SD) rats. METHODS In acute toxicity study, rats (10 males and 10 females) were intravenously administered Danshen injection dose of 32g/kg body weight, two times in one day. General behavior, adverse effects and mortality were recorded for up to 14days post treatment. In the sub-chronic study, Danshen injection was given intravenously at the doses of 0, 1.92, 5.76, and 19.20g/kg per day (n=15/group each sex) for 13weeks to rats. Animal body weight and food intakes were observed weekly. Hematological, biochemical parameters and organ weight were determined in all animals at the end of the 13-week administration and 2-week recovery. However, histological examinations were carried out in the control and high-dose groups only. RESULTS In acute study, the sign of struggling was observed in some animals at the moment of intravenous administration. No deaths and other signs of toxicity occurred in any of the animals tested during the 14days of the study. In sub-chronic study, Danshen injection did not result to death, adverse effects or dose-dependent changes in food consumption, but had an effect on body weight gain. Some statistically significant differences were observed in hematological and biochemical parameters, as well as in some organ weights of both male and female rats treated with Danshen injection. In these changes, the significant decrease in triglycerides and increase in total bilirubin were considered related to treatment, indicating the lipid-modulating activity of Danshen. Histopathological examinations of the injection site showed that Danshen injection could cause dose-dependent focal inflammation. There was no abnormality of other organs noted in both gross and histopathological examinations. CONCLUSIONS The results showed that acute or sub-chronic administration of Danshen injection was low or non-toxic in male and female rats, and the no-observed-adverse-effect-level for sub-chronic administration of Danshen injection dose was 5.76g/kg bw/day, which was suggested that it was safe in clinical use.