Abstract One hundred and ninety-nine patients who received radiation therapy for a primary brain or pituitary tumor were studied for radiation-induced soft-tissue reactions of the cranium, scalp, ears and jaw. The frequency of these reactions was studied as a function of. the radiation dose 5 mm below the skin surface, dose distribution, field size and fraction size. Forty percent of patients had complete and permanent epilation, while 21% had some other soft-tissue complication, including scalp swelling—6%, external otitis—6%, otitis media—5%, ear swelling—4%, etc. The frequency of soft-tissue reactions correlates directly with the radiation dose at 5 mm below the skin surface. Patients treated with small portals (<70 cm 2) had few soft-tissue reactions. The dose to superficial tissues, and hence the frequency of soft-tissue reactions can be reduced by: (1) using high-energy megavoltage beams; (2) using equal loading of beams; and (3) possibly avoiding the use of electron beams.