Human or horse, experiencing the irritations of pollen, tree and grass allergies can cause real misery.
It's all down to an over-reaction by the body's immune system. So, while a fairly swift fix can be sought by blocking the histamine and associated symptoms, what we'd rather not do is end up with scripts of inhalers and inappropriate antibiotics (pollen response is not bacterial!), which would suppress and inhibit the immune system, while adding to the system's toxic load without addressing the root of the problem.
Thankfully there's a beneficial range of nature's organic best to help.