TL;DR: It is normal for cats to eat grass to settle their stomachs, often resulting in vomiting clear liquid; however, you should monitor for lethargy or loss of appetite and take a photo of the vomit for your vet.
Why is my cat eating grass and vomiting clear liquid?
It is common for cats to consume grass and subsequently vomit. This behavior is often an instinctual way for cats to settle an upset stomach or to help expel indigestible matter like fur or feathers. The clear liquid you see is typically gastric juice or saliva, which is brought up along with the grass blades during the regurgitation process.
How do I know if my cat's vomiting is an emergency?
- Consider this a low-urgency situation if your cat is still energetic, eating regular meals, and using the litter box correctly.
- Monitor for a "digestive reset" where the cat returns to normal behavior immediately after.
- Increase the urgency level if the vomiting happens multiple times in a single day or if the cat stops eating entirely.
How does taking a photo of the vomit help with my cat's triage?
- Capturing a clear photo of both the vomit and the grass provides vital clues for a veterinary professional to determine liquid consistency.
- Photos help identify hidden blood, which can appear pink or look like coffee grounds.
- Visuals allow a vet to rule out the presence of parasites or foreign objects.
- Providing visual evidence leads to a much more accurate triage than a verbal description alone.
Clinical Context (Merck Veterinary Manual)
In cats, vomiting, including the ingestion of grass followed by vomiting of clear liquid, can stem from various causes such as dietary indiscretion or intolerance, parasitic infection, bacterial or viral gastroenteritis, anxiety, or motion sickness. Careful examination of the oral cavity should be performed to check for foreign material like yarn, thread, or needles. Initial treatment involves withholding food for a short period, feeding an easily digested diet, and offering small amounts of water frequently. Careful monitoring for persistent vomiting, depression, abdominal discomfort, and/or fever is critical, and reevaluation is warranted if vomiting persists. Abdominal palpation should be performed to look for signs of a foreign body or abdominal discomfort. Abdominal radiographs should be performed, looking for radiopaque foreign objects or signs of intestinal distention, indicating possible obstruction.
Chapter: Pharmacology
Source: The Merck Veterinary Manual, 11th Edition (Page 2547)