Some customers will prefer to use one product to treat their hayfever symptoms. Antihistamine tablets and syrups work by blocking the action of histamine, which is one of the chemicals released when a susceptible person encounters pollen. These products tend to start working quickly, relieve most allergy symptoms and can be taken as sufferers notice symptoms appearing or on a daily basis.

Oral antihistamines are separated into two groups:

1. Older compounds €“ the most common example is chlorphenamine (e.g. Allercalm Allergy Relief, Piriton Allergy). This is a relatively non-specific antihistamine and one of its drawbacks is that it can cause drowsiness. Older antihistamines have a shorter duration of action and so need to be taken more frequently (e.g. every four to six hours). However, these products are often more affordable, which makes them appealing to some customers.
2. Newer compounds €“ examples include acrivastine (e.g. Benadryl Allergy Relief), cetirizine (e.g. Benadryl One A Day, Benadryl Allergy Oral Solution, Piriteze Allergy Syrup, Pollenshield, Zirtek) and loratadine (e.g. Clarityn). Drowsiness is not usually a problem with these products, plus they tend to have a longer duration of action, so don't need to be taken so frequently.