After a brief recall of toxicological data about germanium compounds, the authors relate subacute and subchronic oral toxicities of beta bis carboxyethyl-germanium sesquioxide in rats. During 28 days and six months, male and female animals have received 1 mg/kg/day. No particular toxic symptoms, no behaviour trouble except a small decrease of body weight, in male rats, at the end of the 6-month experimentation, were observed. A light decrease of erythropoiesis and a general stimulation of cellular metabolism has been noticed after 28 days. The only marked effect was a moderate renal deficiency characterized by a tubular disease with presence of cylinders, swelling of tubulus cells and floculus amounts after 6 months. Germanium urinary excretion was constant and linked to the received dose. Six months later, no preferential accumulation in organs was observed