Always consult with your Vet before using herbal remedies with other, prescribed, medications.

What actually is it?

Garlic (Allium sativum) originally came from Asia, but is now found throughout the world and is considered one of the most important herbs, being used in foods and medicines. It was found that Egyptian pyramids construction workers ate large amounts of garlic to protect themselves from diseases. Gravediggers in early 18th Century in France drank garlic crushed up in wine to prevent the plague that killed so many people in Europe. And during both World Wars, soldiers were given garlic to prevent gangrene.

Garlic is antiviral, anti-fungal and antibacterial and has been prized since the first records of civilization for its uses in treating wounds, infections, tumours, and intestinal parasites.

Modern scientists in numerous clinical trials have concluded that garlic lowers cholesterol and blood pressure, thins the blood (which reduces your risk of heart attack and stroke by preventing hardening of the arteries) and fights bacteria like an antibiotic, some viruses and fungal infections, in ailments such as colds, coughs, bronchitis, gastrointestinal problems, and menstrual pain. Garlic is reported to actually be even more effective than penicillin against certain diseases like typhus, and works quite well against strep, staph bacteria, cholera, dysentery and enteritis. And even more! Garlic increases the activity of white blood cells (the cells central to the activity of the entire immune system) thus building the immune system up. But the biggest draw in this day and age is that garlic is thought to have properties that may help prevent cancer.

Uses in rats

Respiratory problems - can open up lungs and bronchial tubes.
Tumours - may possibly inhibit tumour cell formation (research is currently being carried out by the NCI into this).
General Immune System builder.
Rat high blood pressure (!)

Dosages

Try giving it in capsule form or pour the oil over the rat food. Your rat may take it in raw form, but going from the reaction mine had with this, it doesn't seem likely!

Toxicity

Large quantities may lead to stomach upset! However, in a recent study, it was found that you would need to give the average rat (approx. 350g in weight) 10.5ml(!) of garlic extract before any signs of side-effects show. So, giving even 1ml should not show any harmful side-effects.

References: [13 (5,6,7)]