The bioavailability of methotrexate 10 mg tablets has been determined to be 62±16%. After administration of a dose of 30 mg/m
2 a maximum plasma concentration of ca. 20. 10
–7 mole/l was found after ca. 1.7 h. The methotrexate plasma half-life was 2.4 h. It was concluded that the 10 mg tablet formulation at the dosage investigated is a suitable clinical methotrexate preparation.