Astanga Hrudaya
उद्वेजयति जिह्वाग्रं कुर्वंश्चिमिचिमां कटुः। स्रावयत्यक्षिनासास्य कपोलौ दहतीव च॥५॥
Katu (pungent): Katu (pungent) stimulates the tip of the tongue, causes irritation, brings out secretions from the eyes, nose and mouth and causes burning sensation of the cheeks.
english translation