Version 1.0.0, February 2026. 003074-NDSS-W Key facts Complementary medicines are non-prescription medicines that contain ingredients such as vitamins, minerals or plant material. Your blood glucose level can go too high or low when taking some complementary medicines. There can also be other side effects with complementary medicines. It is important to check with your health professional before taking any complementary medicines. Related pages Medicines for diabetes All about insulin Blood glucose monitoring Healthy eating Find a health service Find a health professional or pharmacy in your area. On this page About complementary medicines Unwanted effects of complementary medicines Types of complementary medicines that can affect your diabetes Safety of complementary medicines When to see your health professional What this means for you Many people take complementary medicines for different reasons. It’s important to know that while these products may be natural, they can have side effects. They can also change how your diabetes medicines work. So, always talk with your health professional if you are planning to use any complementary medicines. If you’re not sure, it’s best to ask before taking anything. About complementary medicines Complementary medicines are sometimes called herbal, traditional or natural medicines. They include: vitamins and minerals natural, plant-based, and herbal remedies aromatherapy oils homeopathic products. Complementary medicines can come in different forms, such as: tablets creams drops liquids powders. ‘Complementary’ means that these products can be used with standard medical treatments – they do not replace them. You can usually get them without a prescription from a: supermarket health store pharmacy. Complementary medicines can change how your diabetes medicines work. Always talk to your doctor or pharmacist before starting any new product. Do not stop taking your regular medicines before checking with your doctor. Unwanted effects of complementary medicines Complementary medicines can have unwanted effects. They can: affect your blood glucose levels change how your medicines work interact with alcohol cause an allergic reaction cause side effects This is why it is so important to check before taking any complementary medicines. Talk with your diabetes health professional about any complementary medicines you use or plan to use. Types of complementary medicines that can affect your diabetes Some complementary medicine products have been shown to: change how your diabetes medicines work raise or lower your blood glucose levels. Examples include: Aloe vera Putting aloe vera on your skin is unlikely to affect your diabetes. But taking aloe vera tablets can add to the effect of some diabetes medicines. This can lead to low blood glucose levels (hypoglycaemia). St John’s wort St John’s wort can affect the way your liver breaks down some diabetes medicines. As a result your blood glucose levels may become too high or too low. Niacin High doses of niacin may raise your blood glucose levels. It is not clear why this happens. It may be that niacin makes your body less sensitive to insulin. Ginseng Ginseng may help your body make more insulin. If you are taking diabetes medicines as well as ginseng, this may cause your blood glucose levels to become too low. Chromium Chromium supplements may affect several diabetes medicines, including insulin and metformin. Chromium can increase your risk of low blood glucose levels by changing the way your diabetes medicines work. Safety of complementary medicines In Australia, complementary medicines must be listed with the TGA (Therapeutic Goods Administration) to be sold. This means that they are likely to be safe when used as directed. It does not mean they are safe to mix with other medicines, or that they have been tested to see if they work. Some large research studies have shown that certain complementary medicines have benefits for specific conditions. But most have not been tested in this way. Buying complementary medicines from overseas websites is risky. These products: may be contaminated may contain unlabelled ingredients may not be listed by the TGA may not meet Australian safety standards. If you are unsure, talk to your health professional. When to see a health professional Check with your doctor, nurse practitioner, diabetes educator or pharmacist before taking any complementary medicines. Before using complementary medicines, ask: Is it safe? Will it work? Will it affect my diabetes? Are there any risks? What this means for you Complementary medicines can affect your diabetes and have side effects. They can affect how your diabetes medicines work and can cause your blood glucose levels to go too high or low. Make sure to always check with your health professional before taking any complementary medicines, including tablets, creams, liquids or powders. More information and support Call the NDSS Helpline on 1800 637 700 to ask to speak to a diabetes educator Find out more about diabetes and how to manage your condition by accessing support programs and information sessions. For information on complementary medicines, visit the Therapeutic Goods Administration website or the NPS MedicineWise website. Disclaimer This information is intended as a guide only. It should not replace individual medical advice and if you have any concerns about your health or further questions, you should contact your health professional. Sources Therapeutic Goods Administration (2025). Understanding complementary medicines. Gupta RC et al (2017). Interactions between antidiabetic drugs and herbs: an overview of mechanisms of action and clinical implications. Hunter J and Harnett JE (2023). Interactions between complementary medicines and drugs used in primary care and oral COVID-19 antiviral drugs. Mayo Clinic (2025). Niacin. National Institutes of Health (2022). Chromium.
