The aim of this study was to compare the duration of subcutaneous injection of Clexane on the bruising caused by the same. The sample included 80 patients with ACS under treatment with Clexanein CCU and Post CCU wards. For each patient, two 10-second subcutaneous injections (experimental group) and a 30-second injection (control group) of Clexane were performed in the abdominal area. The interval between injections was 12 hours and the bruising was measured using a flexible plastic ruler 48 and 60 hours after each injection. The size of bruising caused by 30-sec. injections was significantly less than that of 10-second injections. The average size of bruising for30-second injections in 48 and 60 hours after injection was 15.65 ±10.67 and 12.98 ± 8.12respectively. No bruising conditions observed 48 and 60 hours after 30-second injections were significantly lower than after 10- second injections. In most cases, bruising after 10- and 30-second injections was significantly higher in women than in men. There was no significant difference between bruising and age. It is suggested that the subcutaneous injection duration be increased to 30 seconds to enhance the quality of care and minimize the unpleasant and stressful experience for patients.