Baking soda is great for a number of things, including relieving itchy skin from insect bites or a rash from cosmetics and other irritants.
Why it works: Your skin feels itchy from insect bites because of the insect’s acidic sting/venom. As baking soda is alkaline, it quickly neutralises the acid, thus soothing the itch. Baking soda is also a great at drying any itchy bumps or a rash on the skin if your itchiness is caused by allergies or cosmetics. (This drying effect is what makes it so good for cleaning oily skin!)
How to do it: Just apply some baking soda mixed with a tiny bit of water to turn it into a paste and apply to your itching skin and bumps.
[Note: For pet owners, using baking soda on itchy skin is also much better than over the counter ointments as baking soda is not harmful if your pet licks you.]