I used to use that when visiting anybody who had cats. I used it simply because it was the cheapest antihistamine at about $2.75 per hundred pills at Walmart and was supposed to be the least sedating of the OTC allergy pills. This was before any of the "non-sedating" antihistamines went OTC (though Claritin [loratadine] only gets to be labeled "non-sedating" because the recommended dose is too low to be effective for many patients even according to the FDA).The anti histamines Chlorpheniramine and Diphenhydramine (Benadryl) are mentioned on the anxiolytic page on wikipedia, but I've not tried them yet.
L-Theanine works for me when I take 500 mg at once, but only at that dosage. Anything less doesn't do much for me.I've tried Valerian Root, L-Theanine, St. John's Wort etc. It is all crap. None of it works.