What Is IV Therapy?

IV (intravenous) therapy is a way of giving medicine, nutrients or fluid directly into a vein, bypassing the digestive system entirely. Because nothing has to pass through the stomach or intestines first, the body absorbs 90 to 100% of what’s delivered, compared with less than 50% for tablets taken by mouth. IV therapy is one of the most common procedures in modern hospital medicine, and is increasingly used in cancer care to support patients during chemotherapy, radiotherapy and recovery.

Medically reviewed by Dr Saskia Kloppenburg Vieth (GMC 7541548), June 2026.

What is intravenous (IV) infusion therapy?

In simple terms, intravenous (IV) therapy is a method of delivering medicine, nutrients or other fluids directly into the bloodstream through a vein, so they can be immediately absorbed and used in the body. The intravenous route is much faster than the oral route because the digestive system is bypassed and the therapy is taken directly to the organs via the circulatory system. The absorption rate for IV therapies is 90 to 100% compared with possibly less than 50% for oral therapies.

Intravenous infusions are not the same as intravenous injections. Direct injections deliver therapy quickly, which can be necessary for certain medicines and in specific situations. IV infusions are administered over a longer period of time, using a larger volume of fluid — typically 30 to 90 minutes per session.

How does IV therapy compare with tablets and injections?

Most people are familiar with taking medicine by mouth, but oral, intramuscular and intravenous delivery work very differently:

Oral (tablets, capsules, liquids): Absorbed via the digestive system. Absorption is typically 20 to 50%, slower (30 to 90 minutes), and depends on what you’ve eaten and how well your gut is working.
Intramuscular injection: Delivered into a large muscle. Faster than oral, but limited in volume — you can only inject a small amount at a time.
Intravenous infusion: Delivered directly into a vein over a controlled period. Absorption is 90 to 100%, the dose is precise, and much larger volumes can be safely given. The clinician can adjust or stop the infusion at any point.

For cancer patients whose digestion has been affected by chemotherapy, or who can’t keep tablets down because of nausea, IV delivery often becomes the only realistic way to maintain therapeutic nutrient levels during treatment.

Is IV therapy new?

Modern intravenous therapy has been around for less than a hundred years, although the concept of delivering medicines directly into the veins is centuries old. Early attempts were hampered by primitive equipment, poor understanding of the body and lack of effective sterilisation techniques. Tremendous advances have been made in the last 25 years, and IV therapy is now one of the most common procedures in modern medicine.

What happens during an IV therapy session?

An IV therapy session is straightforward and comfortable. After a clinical review of your medical history and current treatment plan, you’ll be seated in a comfortable treatment chair. A registered nurse will gently place a small cannula into a vein in your arm or hand, and the prescribed infusion will run at a controlled rate over 30 to 90 minutes. Most patients read, work on a laptop or simply rest during this time.

Your vital signs are monitored throughout, and the infusion can be paused or adjusted at any point. Most people feel well immediately afterwards — some report a boost in energy, others feel slightly tired. Light meals and good hydration before and after the appointment help you feel comfortable throughout.

Uses of IV therapy

Until relatively recently, IV therapy was used mainly in hospital settings, commonly to deliver rehydration and other medicines to patients. It is also the obvious route to use when patients are unable to take oral medication. However, IV therapy is now an increasingly popular choice in cancer care and other clinical settings, with advanced delivery techniques and equipment that ensure a comfortable and convenient experience. IV infusion can deliver a wide range of therapies, from immune system support and recovery to ongoing complementary care alongside conventional cancer treatment.

Who can benefit from IV therapy?

There is growing evidence that IV therapies can benefit a wide range of people, particularly those experiencing challenges to their immune system. At Wellbeing Medical Group, we specialise in IV therapies for cancer patients — supporting people through chemotherapy, radiotherapy, immunotherapy and surgery. Our therapies include high-dose vitamin C IV therapy, mistletoe IV infusion therapy, curcumin IV therapy, helleborus IV therapy and wormwood IV therapy. We also offer ozone therapy at our London clinic. Each therapy is tailored to your diagnosis and designed to work alongside your hospital treatment.

IV therapy at Wellbeing Medical Group

Wellbeing Medical Group is a CQC-regulated integrative cancer clinic based near Tower Bridge in London. We offer a range of intravenous infusion therapies designed specifically for cancer patients, working alongside your NHS or private oncology treatment. Every protocol is personally designed by Dr Saskia Kloppenburg Vieth based on your diagnosis, treatment plan and medical history.

If you are experiencing cancer treatment side effects such as fatigue, nausea or immune suppression, our IV therapies may help support your wellbeing during treatment. We also provide broader supportive cancer care guidance covering nutrition, supplement safety and emotional wellbeing, and a dedicated comprehensive cancer pain management service. For patients who cannot travel easily to London, our cancer care at home service delivers IV infusions across the UK.