Abstract: Compositions of matter comprising a substituted cyclodextrin and cytotoxic compound, especially cytotoxic drugs such as antibiotic, anti-fungal and anti-neoplastic, drugs are claimed. The compositions cause significantly less ulceration compared to the same formulation of cytotoxic compound without cyclodextrin compound when extravasated. The compositions may also cause less vascular irritation compared to the same formulation of cytotoxic compound without cyclodextrin when administered intravenously without extravasation. Compositions of matter comprising watersoluble cytotoxic agents, especially anti-cancer drugs and anti-ulceration effective or anti-irritation effective amounts of cyclodextrin compounds are also claimed. Methods for reducing the likelihood of ulceration and or irritation when administering the compositions according to the invention are also disclosed and claimed.