There are many confusing terms which presently apply to the group of clinical problems accompanied by middle ear effusion manifestations. Out of this chaos there is a need for logic and simplicity. All of the middle ear effusions are examples of the broadly descriptive categorical term "otitis media" meaning "inflammation" of the middle ear which includes examples of frank "infection" as well. Based upon clinical and laboratory observations there are essentially four types of intrinsically occurring middle ear fluid which, along with clinical findings, provide the means of identifying the clinically descriptive term which should be used: 1) serous fluid (serous otitis media); 2) mucoid fluid (mucoid otitis media, secretory otitis media, glue ear); 3) bloody fluid (barotrauma, aerotitis); 4) purulent fluid (purulent or suppurative otitis media); and 5) any combination of the above four (e.g., seropurulent otitis media, serosanguineous otitis media, mucopurulent otitis media, etc.).