Preclinical safety of reamberin, a preparation of succinic acid intended for the treatment of patients with shock conditions of different etiology, and remaxol a drug intended for the treatment of patients with liver dysfunction caused by acute intoxication was performed. Both medicines belong to the 5th class of practically non-toxic drugs. Their administration to experimental animals for 30 days did not cause toxic effects on the functional and morphological state of main systems and organs. Both medicines do not affect specific (humoral and cellular) and non-specific immune response and do not cause sensibilization, mutagenic, embryotoxic and teratogenic effects, and also do no alter parameters of reproductive functions of rats.