What vitamin deficiency causes mouth ulcers?

Oral ulcers—commonly known as “mouth sores”—are a frequent ulcerative condition affecting the oral mucosa. They commonly occur on the inner surface of the lips, tongue, ventral surface of the tongue, buccal mucosa, vestibular groove, and soft palate—areas where the mucosa lacks keratinization or is only minimally keratinized. So, which vitamins are typically deficient in individuals with oral ulcers? The following section addresses this question.

Which vitamins are commonly deficient in oral ulcer patients?

A common cause of oral ulcers is deficiency of trace elements, particularly vitamin C and vitamin B₂. Vitamin B₂ plays a crucial role in maintaining the integrity of skin and mucosal tissues, while vitamin C deficiency can delay wound healing. However, oral ulcers have multiple etiologies; deficiency of these vitamins does not inevitably lead to ulcer development. Supplementing the relevant vitamins may support ulcer healing as an adjunctive measure.

The causes of oral ulcers are multifactorial and often involve immune dysregulation. Other contributing factors include trace element deficiencies, psychological stress or anxiety, genetic predisposition, and local trauma. For instance, individuals experiencing high work-related stress, persistent anxiety, frequent late-night activity, selective eating habits, regular consumption of spicy or irritating foods (e.g., barbecued dishes or hotpot), and insufficient physical activity are at increased risk for recurrent oral ulcers. Similarly, sharp tooth cusps within the mouth—or habitual cheek or tongue biting—can induce traumatic ulcers.

Knowledge Extension: Key Precautions for Oral Ulcer Patients

Patients prone to recurrent oral ulcers should avoid foods that may traumatize the oral mucosa—including coarse foods (e.g., sugarcane, shellfish with hard shells), hard or crunchy foods (e.g., puffed snacks, fried foods), and excessively hot foods. A balanced diet is recommended, with reduced intake of spicy or irritating foods (e.g., barbecued items or hotpot) and increased consumption of fiber- and vitamin-rich fruits and vegetables. Daily regular bowel movements are also advised. Maintaining consistent sleep-wake patterns—including avoiding late nights and ensuring adequate, high-quality sleep—helps sustain emotional well-being and reduce anxiety. Good oral hygiene is essential: brush teeth twice daily, rinse or brush after meals, floss regularly, and promptly treat residual tooth roots or crowns to eliminate local irritants and prevent mucosal injury. Regular physical exercise is encouraged to enhance overall immune function.

The above outlines the relationship between oral ulcers and vitamin deficiencies. We hope this information proves helpful to you.