Antihistamines are mainly used to treat seasonal allergic rhinitis (hay fever), urticaria (hives), pruritus (itching) and insect bites and stings. They may also be used to help reduce nausea and vomiting, and in the emergency treatment of anaphylaxis - a severe allergic reaction. The side-effects most commonly experienced are minor. In addition, Antihistamines are a class (group) of drugs used in the treatment of allergic disorders and some other conditions. They include: acrivastine, cetirizine, desloratadine, fexofenadine, levocetirizine, loratadine, mizolastine, alimemazine, chlorphenamine, clemastine, cyproheptadine, hydroxyzine, ketotifen and promethazine. These also come in various different brand names, Kaplan (2013, May 9). They can be taken as tablets, syrups or nasal sprays, and some come in droplet form for use in the eyes. This case study will discuss the application of promethazine on a patient who is suffering from hives. It will also emphasize on different uses, contraindication, and the side effects of promethazine. Lorraine Mark is a 24 years female from Kerema in the Gulf province. Married to Freddy Kamaho from Bulolo in the Morobe province and had three children. Her husband is a warder and they reside at Bomana correctional services institute in Port Moresby. On 18th April 2013, she showed up at Pacific Adventist day clinic with the complaint of hives all over her body. It was first felt itchy and she began to scratch it without ceasing. It was started 3/7 ago and she can’t tolerate with it anymore. After viewing her history of past illness the nurse found out that she had previously treated with urticaria. She was previously prescribed with promethazine (Phenergan) and it helps her to recover from the same condition as at present. However, she did not complete all the doses as prescribed by the nurse earlier. She stopped taking it when all the hives from her body was disappeared and though she was fully recovered. The nurse prescribes the same medicine and warned her not to skip or deliberately ignore the medicine when the hives disappeared from her body. She informed her of the contraindication and expected effects which the patient may encounter during the administration of the medicine. She told her to take Phenergan tablets 25mg orally for as long the symptoms persist, or as normally recommended by doctor but for no longer than 10 consecutive days. She was given 24 tablets (3/24) for the next seven days. During the administration of the medicine at home she often encountered sleepiness, dizziness and blurred vision. For that reason she sometimes skips the doses as scheduled by the nurse. On her second visit to the clinic she was told not to take double dose to make up the missed dose but to continue with the remaining dose. She also informed her of the adverse effects when taking this medicine. After three days he was fully recovered and all the hives were disappeared. Phenergan can be used in many ways to treat different allergic reactions to food, chemicals, dust, insect bite, and pollen of the flower. These allergic reactions can cause the body to produce chemical called histamine. The release of histamine causes allergic symptoms which can include sneezing, runny or watery eyes and nose, itching and skin rashes. Antihistamines like Phenergan reduce the effects of histamine and help to relieve these symptoms. In addition, Phenergan can also be used to treat sickness, vertigo (loss of balance or dizziness), and to prevent travel sickness. Because Phenergan causes drowsiness, it may also occasionally be used for short periods of time to treat insomnia (difficulty sleeping) in adults, Powell and Clark (2013, May 4). The different forms of Phenergan were stored at different temperature based on the route of admission. Tablets, syrup and injection should be stored at room temperature, between 15 oC to 25 oC (68 F to 77 F).