Cats deficient in iron, zinc, calcium, or sodium are instinctively drawn to substances they sense contain these minerals. Clay-based litters (particularly bentonite) contain minerals — an anemic or deficient cat may find this "attractive" in a way that's hard to explain. This is distinct from pica: when the underlying medical cause is treated, the eating stops.

Anemia/deficiency signs:

• Pale or whitish gums
• Unusual fatigue, reduced activity
• Coat becoming dull, weight loss
• Also eating soil, chalk, or plastic alongside litter

Some cat litters contain corn, wheat, tofu, grain, or lavender scents. A cat — especially a kitten — may associate these smells with something edible. This curiosity-driven behavior is usually temporary, but if the litter is clumping type, the risk cannot be ignored.

Signs:

• Interest only in the new litter, none in the old one
• Eating after sniffing rather than upon first contact
• Tries it a few times then stops — not compulsive

In middle-aged and senior cats, hyperthyroidism can amplify eating compulsions — including toward non-food items. Diabetic cats can experience similar behavior driven by tissue-level hunger. If litter eating began suddenly and the cat is over 7 years old, a metabolic workup should be considered.

Cats sometimes turn to grass, soil, or textural materials like litter to alleviate stomach nausea — a misdirected version of the grass-eating instinct that normally seeks plant fiber. Cats with inflammatory bowel disease (IBD) or chronic gastritis may show this behavior more frequently.

Signs:

• Vomiting before or after meals
• Apparent relief after eating litter
• Also eating grass or plants

Kittens separated from their mother before 4 weeks of age continue to seek oral satisfaction throughout life. These cats may suck and chew on fabric, plastic, or litter well into adulthood. Behavior often begins around 6–8 months of age and is triggered or worsened by stress.