Allergy ' ingredient - the chemical that actually treats the symptom. Protections and quality control apply equally to all branded and non branded products. The non branded product must meet the same quality standards as the branded version. Packaging may vary, but the items are identical and the results will be the same.How to use Allergy & Hayfever Relief One A Day Tablets:Most people can take this medicine without any problems, but sometimes you may notice some side effects which may include: headache, nervousness and fatigue, in children, drowsiness, headache, increased appetite, difficulty in sleeping, in adults.Very rarely, severe allergic reactions (difficulty in breathing, wheezing, itching, hives and swelling), dizziness, fast heart beat, palpitations, nausea, dry mouth, upset stomach, changes in liver function, rash, hairloss and tiredness. If you are worried by these or any other side effects, you should discuss them with your doctor.