Infantile hemangiomas are not usually dangerous and generally go away on their own. In the past, doctors tried shrinking them with corticosteroids or zapping them with lasers, but the former may cause long-term side effects, and the latter does not affect deep lesions. Now, a surprising new treatment has proven to be faster, safer, and more effective.

Pediatric dermatologist Seth Orlow, MD, PhD, reduces the benign growths with propranolol, a drug used to control heart disease and high blood pressure in adults. “This medication, a beta-blocker, has revolutionized the way we treat hemangiomas,” explains Dr. Orlow, the Samuel Weinberg Professor of Pediatric Dermatology and chairman of the Ronald O. Perelman Department of Dermatology at NYU Langone. “Parents have told me they see a difference after just days of treatment.”

Hemangiomas—sometimes called strawberry marks for their distinctive color—occur when blood-vessel cells proliferate for unknown reasons, creating a cluster of new microscopic vessels. A growth can appear as a red bulge on the skin or, if it’s located deeper under the skin, as a bluish lump. A hemangioma typically shows up shortly after birth as a red dot or small bruise on the head, face, or neck. It grows rapidly during the first four to six months, then shrinks and fades over the next five years or so. In most cases, the growth is painless and benign, but a hemangioma located near the nose or mouth may hinder breathing while one near an eye may affect vision.

Propranolol, administered in liquid form, may be used in children who are at least five weeks old. How the medication works is unclear, but it is known to constrict blood vessels, so this may slow blood flow within the growth. It also seems to keep the growth from proliferating, perhaps by killing off the cells that cause it. Side effects are uncommon, short-term, and relatively manageable.