Dry air can particularly worsen a dry, irritating cough, so getting an air humidifier can be really useful! Alternatively, you can place a bowl of water on your radiator so that as it warms it releases moisture into the air. Just be careful that your home doesn’t get too humid, as this could cause damp and mould which aren't good for a cough either!
Eating a clove or two of fresh garlic a day may indeed keep the doctor away, in part because it has immune-boosting, antibacterial, antiviral, and anti-fungal effects. Many of garlic's therapeutic effects are derived from its sulfur-containing compounds, such as allicin, which are also what give it its characteristic smell. In general, garlic's benefits fall into four main categories: 

Cancer cells are unable to use ketones for their energy source. They rely on glucose and glutamine for metabolism. Thus, if they do not have access to glucose, they rapidly begin to die. When a person uses the ketogenic diet, they create a condition where there is a reduced level of glucose in the blood and there are elevated levels of ketone bodies. The result is that the cancer cells are denied their primary energy source (starved) while all the healthy cells in the body are nourished by ketones.
The aptly named bitter melon is thought to help cells use glucose more effectively and block sugar absorption in the intestine. When Philippine researchers had men and women take bitter melon in capsule form for three months, they had slight, but consistently, lower blood sugar than those taking a placebo. Gastrointestinal problems are possible side effects. You can reverse diabetes with these science-backed strategies.