Cat owners tend to shrug off vomiting as just part of living with a cat. And sometimes it is — an occasional hairball or a too-fast meal coming back up isn't usually cause for alarm. But "my cat throws up sometimes" and "my cat is throwing up regularly" are two very different situations, and knowing which one you're dealing with matters.

The usually-harmless causes

• Hairballs. Cats groom constantly and swallow hair; every so often it comes back up. The occasional hairball is normal.
• Eating too fast. A cat that inhales a meal may bring it right back up, undigested, minutes later. Smaller, more frequent portions or a slow-feeder bowl often fixes it.
• A sudden diet change. Switching foods abruptly can upset the stomach. Transitioning over a week or so helps.
• A little stomach upset. One isolated episode in an otherwise bright, happy, eating-and-drinking cat usually isn't an emergency.

The more serious causes

Frequent or ongoing vomiting can point to something that needs treatment, including:

• A swallowed foreign object or string (string is especially dangerous and never a "wait and see")
• Hyperthyroidism or kidney disease, both common in older cats
• Inflammatory bowel disease, food sensitivities, or parasites
• Exposure to a toxin or a poisonous plant (lilies, for example, are extremely toxic to cats)

When to call the vet now

Some signs mean don't wait: repeated vomiting over a day, blood in the vomit, inability to keep water down, lethargy, hiding, refusing food, a painful or swollen belly, or any suspicion your cat swallowed string or a toxin. A cat that stops eating can become seriously ill faster than many owners expect, so when in doubt, make the call.

Why tracking it helps

Here's something that makes a real difference at the vet: knowing how often it's happening. "Twice this month" and "every day this week" lead to completely different conversations — but most of us honestly can't remember. Jotting down each episode, and whether it was food, hairball, or foam, turns a vague worry into specific information your vet can actually use to help your cat faster.

Your cat can't explain what's wrong. Noticing the pattern — and acting on the red flags — is how you speak for them.