This paper describes Phase I clinical studies of Antineoplaston A2 injections. The studies involved 15 patients diagnosed with advanced neoplastic diseases including cancers of the breast, bladder, lung, kidney, oesophagus, colon and liver, mesothelioma and glioma. Antineoplaston A2 was administered in divided doses daily intravenously through a subclavian vein catheter. The treatment was given from 53 to 358 days. The highest dosage administered was 147 mg/kg/24 h. Only minimal adverse effects were noticed sometime during the treatment, including fever, chills and myalgia. Desirable side-effects included increase of platelet and white blood cell counts, hypertrophy of epidermis and decrease of cholesterol and triglyceride levels. Nine patients showed objective response to the treatment. Cases of complete remission included adenocarcinoma of the lung, mesothelioma, metastatic liver and bladder cancers. In an additional case of breast cancer, the patient obtained complete remission of liver metastasis and stabilization of bone metastases. Partial remission was accomplished in cancers of the breast and oesophagus. Three patients, including cases of adenocarcinoma of the lung, mesothelioma and bladder cancer, were in complete remission for over five years.