Is Giving Blood Safe? Side Effects and Common Myths

Can you catch an infection from giving blood?

No. The American Red Cross says you cannot get AIDS or any other infectious disease from giving blood, because the needles are new, sterile and thrown away after one use.

What side effects can you expect?

Most donors feel fine after donating. Some feel dizzy or tired, and lying down until you feel better is the answer. You are less likely to feel this if you sleep well, eat and drink enough water before donating, and rest afterwards.

If you feel dizzy after donating, avoid any activity where fainting could hurt you for 24 hours.

Does giving blood weaken your body?

An adult body holds about ten times the amount given in one donation. The American Red Cross says your body replaces the loss in a short time: hours for some parts of the blood and a few weeks for others.

Because your body needs iron to make new red blood cells, there is a wait between donations and your hemoglobin is checked before each one.

What does the centre check before you donate?

Before every donation you answer health questions, and the team checks your temperature, blood pressure, pulse and hemoglobin to make sure donating is safe for you that day.

Common myths about giving blood

• “I can’t donate because I take medicine”: most medicines do not stop you from donating; some need a wait after the last dose.
• “My chronic condition rules me out”: many people with chronic conditions donate when they feel well and their condition is under control. Read donating with high blood pressure or diabetes.
• “They turned me down once, so I never can”: even if you were deferred before, you may be eligible now.
• “My blood type isn’t needed”: every blood type is needed, and every type can save a life.
• “Donating could give me a disease”: no, every donor gets new, sterile needles.

Why does regular donation matter?

The World Health Organization says a safe and adequate blood supply depends on a stable base of regular, voluntary, unpaid donors, who are also the safest donors because bloodborne infections are least common among them. About 120.4 million blood donations are collected worldwide, according to the organisation’s latest data.

Check whether you can donate in a minute with Can I donate blood today?.

Frequently asked questions

Sources

This guide is based on the following published sources:

1. Answers To Concerns About Donating Blood American Red Cross
2. First Time Blood Donors Guide American Red Cross
3. Blood safety and availability World Health Organization

Content and links last reviewed: 17 October 2026. How we write the tools

This tool gives general guidance based on published rules, which differ by country and change over time. It does not replace a medical assessment. The doctor at the donation centre always makes the final decision. In an emergency, call your local emergency number.