If your indoor cat has litter box odour....
My adored rescue cat has always had litterbox deposits that, well, ponged to high Heaven! I found the food she was least allergic to (and tried kitty enzymes) yet the pong continued - but reduces ENORMOUSLY on these tablets which she loves! I imagine it is the chlorophyll that reduces the odour if she has four or more a day (she is a small slim very fit and active cat). My cat adores them and so does my dog - long may they make them!