Some years ago, when I cared for a number of rescue cats, my veterinarian and I were faced with a mystery. Some of the cats had diarrhea, recovered, others had it, and then the first one or two had it again. And recovered again. I took one or two cats in for exams but the veterinarian found no problems.
It was summertime. My cats did not run free but enjoyed the outdoors in a long fenced and roofed run. Mystified and exasperated, the vet told me to check around the run to see what was growing there. And that’s where I found the answer to the mystery.
As a budding herbalist, I recognized the plants clinging to the fencing as cleavers, also known by a whole string of colorful names including goosegrass, bedstraw and Robin Run the Hedge. And immediately I knew what was causing the problem. These plants were featured in a book I owned called Wild Teas, Coffees and Cordials by Hilary Stewart. Cleavers belongs to the same plant family as coffee and the author explained how to roast the hairy seeds or burrs and then grind them up to make coffee. Just like our store-bought coffee, the cleavers seed coffee contains caffeine, which, in excess, will cause diarrhea. The cats were getting a caffeine hit each time they swallowed the burrs they groomed from their fur.
Working in the garden today, I found a couple of the cleavers burrs attached to my clothes. They are soft and green now but later in the season they will be hard and brown. Either way they stick. So does the whole plant. And now is the season to see if the cats you care for are being caffeineated.
If you clear a lot of these plants from your cats’ prowling grounds, you might consider using them. Not only do the seeds make a coffee but the plant itself is also both edible and medicinal, traditionally used for skin ailments and detoxing among other uses. It has also been used to strain milk and stuff mattresses. (http://en.wikipedia.org/wiki/Galium_aparine)