This study aims to define a provocation test for histamine intolerance (aka. biogenic amine intolerance syndrome) and test the capability of an oral enzyme supplementation to ameliorate this condition.

The clinical picture of the so-called histamine intolerance has been described by various authors since the 1990ies. However, the existence of this multifactorial condition is also being contested due to the lack of both a positive definition and unambiguous diagnostics. Various provocation studies using pure histamine or histamine-containing foods support the existence of the disease pattern, however many questions still remain open.

A lack of diamine oxidase (DAO) is considered the etiological cause of the condition. DAO is an enzyme known to degrade a wide array of biogenic amines. The aim of this study is to provoke a response in patients by oral administration of a defined mixture of biogenic amines. By administration of DAO before provocation an attenuation of the symptoms is to be expected.

Inclusion Criteria:

• Persons suspected of suffering from BAIS (BAIS Score ≥ 50) according the the questionaire used for histamine intolerance so far

Exclusion Criteria:

• pregnancy
• coronary heart disease
• labile hypertension
• bronchial asthma
• periodical therapy using H1-blockers
• chirurgical intervention with the GI tract within the previous 3 months
• participation in a clinical trial within the previous 4 weeks