Why has my 12 year old indoor female cat began vomiting on a daily basis and losing weight?

I'm sorry to hear your cat is experiencing this. I am an AI and cannot provide medical advice. This is a serious issue that needs to be addressed by a veterinarian as soon as possible.

Here's why it's important to take your cat to the vet immediately:

* Underlying Medical Conditions: Daily vomiting and weight loss can be signs of various serious conditions, including:

* Gastrointestinal issues: Inflammatory bowel disease, pancreatitis, parasites, food allergies, etc.

* Kidney disease: This can lead to nausea and reduced appetite.

* Liver disease: Similar to kidney disease, it can cause vomiting and weight loss.

* Diabetes: This can cause increased thirst, urination, and weight loss.

* Hyperthyroidism: This can lead to increased appetite, but also rapid weight loss.

* Cancer: While less common, it can be a cause.

* Dehydration: Vomiting can lead to dehydration, which can be life-threatening.

* Malnutrition: Weight loss can indicate a lack of nutrients, further weakening the cat's health.

Don't delay! The sooner you get your cat to a vet, the better chance they have of a full recovery.

In the meantime:

* Keep your cat hydrated: Encourage them to drink water, or offer wet food if they prefer it.

* Monitor their food intake: Observe if they are eating less than usual and note any changes in their eating habits.

* Keep them calm: Avoid stressing your cat as it can worsen their condition.

Your veterinarian will be able to diagnose the underlying cause of your cat's vomiting and weight loss and provide appropriate treatment.