Thirty patients (20 adults and 10 children) suffering from nutritional anaemias were treated with folinic acid for 15 days per os at a dosage of 4-8 mg daily. For each patient routine laboratory tests, folic acid assays in the serum and in the erythrocytes have carried out and the clinical parameters have been recorded at the beginning and at the end of the treatment. The results showed statistically significant increase in the number of red cells per cmm, in folic acid content both in the serum and in the erythrocytes; at the same time a decrease of mean corpuscular haemoglobin concentration (MCHC) and mean corpuscular haemoglobin (MCH) was observed.