I use them for my oldest cat Estelle. She sometimes has digestive issues and I found that probiotics keeps things in balance. Or if she has digestive issues, giving her some probiotics mixed into her food seems to straighten things out quickly--either constipation or it's unpleasant opposite. However, the bottle I bought still has about 1/2 in it and I noticed its "best before" date has passed by a month. The stuff lasts forev