Explainers for the things nobody taught you at school and even parents don't always know: how a cold spreads and why it lasts a week, what a painkiller actually does, when leftovers become unsafe, what the humidity meter is telling you. Each page gives the short answer, the mechanism in plain words, what to do, the exceptions, and the sources — so you understand it once and use it for years.
An illness that ends on its own makes almost any remedy look effective; recovery, regression to the mean and placebo feel identical from the inside, and only a control group tells them apart.
Popular cold remedies have modest evidence at best and often none at all; a cold ends on its own, and warning signs need a doctor rather than a supplement.
Colds, flu, and COVID look alike, and a test earns its place when it can change treatment; with severe symptoms or in a risk group, care does not wait for the result.
Several colds a year are normal because immune memory is virus-specific; what deserves a doctor's attention is severe, unusually stubborn or unusually frequent serious infections.
Colds travel by droplets, by indoor air and by hands, and a person is contagious before feeling sick; cold weather alone infects nobody.
Fever, aches and a running nose are the immune response at work, and yellow or green mucus is a normal phase of a cold rather than a sign of bacteria.
When someone at home is ill, cleaner air, hand washing, distance and masks lower the risk for everyone else, and being exposed is still not the same as being infected.
A cold passes on its own, so home measures make the days easier rather than shorter; a doctor is needed if breathing is hard or things get worse after getting better.
A cold is a viral infection that clears on its own and antibiotics do not treat it; a doctor is needed for trouble breathing, for getting worse after getting better, and for a fever that will not settle.
Handwashing works by the moment, not by how dirty hands look: plain soap and water around food, the toilet, coughing and caring for someone sick — it lowers transmission, not symptoms you already have.
Antibiotics act on bacteria, not on the viruses that cause colds; a doctor is needed when the signs point to a bacterial infection or when things get worse instead of better.
