The gingival health of 19 patients with cardiovascular problems who were medicated with nifedipine was compared with a similar cohort treated with atenolol and a control group of healthy patients. In the nifedipine and atenolol groups, patients had been taking their respective medication for a minimum period of 6 months. Plaque scores were similar for all three groups. However, patients medicated with nifedipine had a significantly higher gingival index (P less than 0.005), gingival overgrowth scores (P less than 0.02) and probing sites greater than 3 mm (P less than 0.005) when compared with the atenolol and control groups. 4 patients in the nifedipine group experienced clinically significant gingival overgrowth which required surgical excision. Gingival changes in the nifedipine patients were not related to drug dosage or plaque scores. It is concluded that nifedipine therapy results in significant gingival changes, an effect which may be mediated by the drug's action on calcium transport.