Allergy remedies come in many different "flavours" - there are herbs, homeopathics and nutritionals to name the main types. My main love and my main experience is with Nutritional supplements so that's what we're looking at today.
Vitamin C
The simplest and most straightforward of all natural remedies is vitamin C, usually taken as ascorbic acid which is the cheapest version of vitamin C and the most widely available.
Vitamin C is water soluble and does not build up in body tissues. We need doses of vitamin C spread through the day to cope with allergens causing problems throughout the day.
Dosage depends on several different factors so cannot be the same for all but I use 1 gram tablets commonly available in any health store.