The article reports on the well-known self-healing tendency and radiosensitivity of blastomatous haemangiomas. The change in treatment methods is shown. According to our experience collected during 1950--1964 and 1964--1968 there is a trend towards lower dosage. During the 1969--1976 period, 554 blastomatous haemangiomas were exposed to low-dosage radiation. Sr90 treatment (1000--2000 rd) yielded very good results, soft radiation being somewhat more unfavourable at our dosage level (usually 600 rd) than our previous higher dosage, which means a slight correction towards increasing the dosage should be effected. The overall result is better if treatment is initiated during the first half year of life. Radiation therapy is the method of choice in blastomatous haemangiomas. It should be employed frequently despite the high self-healing quota, since 1. there are practically no unfavourable side effects if the dosage is kept at a low level; 2. retrogression is accelerated; 3. the cosmetic result, which is not always quite satisfactory in self-healing, can usually be improved upon by radiation; and, finally, 4. the risk of ulceration and haemorrhage is reduced.