Food allergies are now almost endemic, it seems to me. There are a number of different remedies for food intolerances, but I always suggest finding the offending thing and eliminating it from one's diet. The preservatives in some wines and some beers, and the additives in some breads are now regularly brought to my notice as causing allergic reactions.
Ideally, remedies should be stored in cool, dry places, perhaps a drawer. The area should be free of any strong smells or volatile substances which might affect the remedies. They should not be kept near celphones or microwaves, and should never be exposed to bright sunlight nor moisture. It has been suggested that some household cleaners, perfumed cosmetics and tioletries, mints, aromatherapy oils like peppermint, camphor, eucalyptus, rosemary, thyme and lavender, may affect the action of remedies. It has also been suggested that coffee may neutralise some of the effect of remedies.
One should not handle the pillules any more than necessary, preferrably flicking them under the tongue from the cap. It is also traditionally recommended that no food or drinks be taken for around 10 minutes before or after taking a remedy.
However, I have been experimenting for some years with these remedies and find that some work perfectly well even when taken with coffee, or when mixed with food or a drink. They also work very well, sometimes, when the recipient does not know he is taking them. For instance, the terribly wrought up businessman whose wife puts Lycopodium in his drinks the night before ultra-stressful meetings, and in the morning his fears have vanished and he goes off with a big grin.