At what temperature (in °C) should a fever cooling patch be used?
Fever refers to an elevated body temperature, and a fever-reducing patch refers to a cooling patch. Generally, when body temperature measured in the mouth, armpit, or rectum is below 38.5°C, a cooling patch can be used, but medical advice should be followed. The details are as follows:

Cooling patches are intended to help relieve symptoms of mild to moderate fever and are typically used when body temperature measured orally, under the armpit, or rectally does not exceed 38.5°C. When body temperature ranges from approximately 37°C to 38.5°C, it is generally considered mild fever. In such cases, patients may consider using cooling patches or other antipyretic medications as directed by a healthcare provider. When body temperature exceeds 38.5°C, cooling patches may not be effective. In these situations, oral antipyretic medications are recommended, such as ibuprofen sustained-release capsules, acetaminophen tablets, or nimesulide tablets, which should be taken strictly according to a doctor's instructions. These medications can effectively reduce fever.
During recovery, adequate rest is important, and excessive fatigue should be avoided. It is also essential to keep the body warm and prevent chilling, which could worsen fever symptoms.