Medicines should generally be stored according to the specific instructions supplied with the product, because temperature, humidity, light, air and other environmental factors can affect medicine stability and effectiveness. A common recommendation for many medicines is storage in a cool, dry place away from direct sunlight and excessive heat, but there is no universal storage condition that applies to every medicine. The MHRA states that many medicines are intended to be stored below 25°C, while some require refrigeration and others need particular protection from heat or light. The patient information leaflet and packaging therefore take priority over generic assumptions about storage.
Temperature is important because excessive heat can accelerate chemical degradation, alter physical properties or reduce the potency of active ingredients. Medicines left in parked cars, hot luggage, sunny windowsills, conservatories or other unusually hot environments can be exposed to temperatures considerably higher than those intended by the manufacturer. The MHRA's 2026 guidance specifically warns that heat and poor storage can affect how well some medicines work and advises people to avoid leaving medicines in cars, suitcases or other places that can become very hot. Heat can be particularly relevant to products such as insulin, certain inhalers, hormone preparations and some contraceptives.
Refrigeration is required for some medicines but should not be assumed for all medicines. Some products remain stable at room temperature and may be damaged by unnecessary refrigeration or freezing, while other products depend on controlled refrigeration to maintain stability. The correct temperature range is product-specific and may be stated explicitly on the label or in the patient information leaflet. For example, a medicine might specify storage below 25°C, while another might require storage at a particular refrigerated temperature. A household refrigerator is also not automatically an ideal environment for every medicine because freezing, condensation and temperature fluctuations can affect some products.
Medicines should normally remain in their original packaging or container unless a healthcare professional or appropriate dispensing system provides an alternative. Original packaging protects the product from environmental conditions and keeps its identity, strength, batch information, expiry date and instructions together. Some products are particularly sensitive to light or moisture and therefore depend on the original container or specific packaging. Removing medicines from their packaging can also increase the risk of confusing one medicine with another, losing expiry information or accidentally taking the wrong dose. Safe storage therefore involves both preservation of the medicine and reliable identification of what the medicine is.
Medicines should be kept securely and out of the sight and reach of children and anyone else who might accidentally or inappropriately take them. This is particularly important for medicines capable of causing poisoning or serious harm in relatively small quantities. Storage also needs to reflect the individual household's circumstances; a location that is technically cool may not be safe if children can access it. NHS hospital guidance recommends keeping medicines out of reach of children and storing them somewhere cool and dry away from direct sunlight.
Bathrooms and areas immediately beside sources of heat are often unsuitable for medicines because humidity and temperature fluctuations can damage some products. Kitchens can also expose medicines to steam, heat and changing temperatures, while windowsills and vehicles can produce substantial heat and light exposure. The MHRA advises keeping medicines somewhere cool and dry, away from direct sunlight, and avoiding bathrooms and areas near heat sources. Travelling requires similar attention: medicines should be protected from extreme temperatures, and products with special storage requirements may require suitable insulated or temperature-controlled arrangements.
Appearance can sometimes provide a warning that a medicine has deteriorated, although visual inspection cannot reliably establish whether a product remains safe. Changes in colour, texture, smell, consistency or tablet integrity can indicate possible damage, particularly following heat or moisture exposure. If a medicine has been stored incorrectly or appears different from normal, it should not simply be assumed to be safe because its printed expiry date has not passed. The MHRA advises speaking to a pharmacist if a medicine may have been exposed to excessive heat or if there is concern that it is not working as it should.
Correct storage is part of maintaining the medicine's stability throughout its authorised shelf life. The expiry date assumes that the product has been stored under the conditions specified by the manufacturer and regulator; it does not guarantee quality after inappropriate storage. Storage requirements can also change after opening for certain medicines, particularly liquids, eye preparations and products whose stability depends on sterile packaging or controlled conditions. The safest approach is therefore to read the product-specific patient information leaflet, follow the label precisely, keep medicines securely stored and ask a pharmacist when storage conditions have been breached or are unclear.
