Which Three Types of People Should Avoid Eating Fennel?
Sep 11, 2025
Source: Cainiu Health
Dr. Sun Lianqing
Introduction
Generally speaking, there is no established saying that specifies "which three types of people should not eat fennel." Individuals who should avoid consuming fennel mainly include those with sensitive gastrointestinal systems, those allergic to fennel, individuals with a hot body constitution, patients with eye conditions, and individuals with hyperthyroidism. In addition, infants and young children should also avoid eating fennel as their digestive systems are not yet fully developed, to prevent possible gastrointestinal discomfort.
Generally speaking, there is no established saying that specifies "which three types of people should not eat fennel." The main groups who should avoid consuming fennel include individuals with sensitive gastrointestinal systems, those allergic to fennel, individuals with a "heaty" body constitution, patients with eye diseases, and people with hyperthyroidism. Detailed explanations are as follows:
1. Individuals with Sensitive Gastrointestinal Systems
Fennel contains volatile oils that can irritate the gastrointestinal mucosa. Those with weaker gastrointestinal function may experience discomfort such as abdominal pain, diarrhea, and nausea after consuming fennel, which could increase the burden on the gastrointestinal system. Therefore, it is not recommended for these individuals to consume fennel.
2. Individuals Allergic to Fennel
Components in fennel may act as allergens, triggering allergic reactions. Symptoms such as skin itching, rashes, and difficulty breathing might occur after consumption, and in severe cases, these reactions could endanger health. Therefore, individuals with such allergies should strictly avoid consuming fennel.
3. Individuals with a "Heaty" Body Constitution
From a Traditional Chinese Medicine (TCM) perspective, fennel is considered warm in nature and has functions of warming the kidneys and liver, dispersing cold, and relieving pain. Individuals with a naturally "heaty" constitution are prone to symptoms such as dry mouth, sore throat, and constipation, commonly referred to as "internal heat." Consuming fennel may intensify internal heat and worsen these symptoms, which is detrimental to regulating overall body condition. Therefore, it is not advisable for them to consume fennel.
4. Patients with Eye Diseases
Certain components in fennel may affect blood circulation in the eyes or exacerbate ocular inflammation. For individuals suffering from eye conditions such as conjunctivitis, keratitis, or glaucoma, consuming fennel may worsen symptoms like redness and eye pain, hindering recovery. Therefore, it is best to avoid eating fennel.
5. Patients with Hyperthyroidism
Fennel contains small amounts of goitrogenic substances that may interfere with thyroid hormone synthesis. Patients with hyperthyroidism already have excessive thyroid hormone secretion, and consuming fennel may affect disease management, potentially worsening symptoms such as palpitations, hand tremors, and excessive sweating. Therefore, it is not recommended for these individuals to consume fennel.
In addition, infants and young children have not fully developed digestive systems, so they should also avoid consuming fennel to prevent gastrointestinal discomfort. Furthermore, in daily life, fennel consumption should be moderated. Even for individuals who are suitable to consume it, excessive intake may lead to bodily discomfort. Maintaining a balanced diet is more important for overall health.
