Because interdental and subgingival sites are relatively inaccessible to mouthrinsing, they necessitate alternative methods of application of anti-plaque chemicals. These include routine oral hygiene aids, surfactants to enhance uptake and retention of antimicrobials, gels and periodontal dressings. The principal modes of application that have received attention recently, apart from the systemic route, are syringe and pulsated jet irrigation and slow release compounds. Slow release devices currently receiving attention may be classified as membrane diffusion, solution of drug in polymer and solid drug dispersed in polymer matrix. The most widespread dental instance of a slow release device appears to be the use of varnishes and resins to carry fluoride. Recent attempts at devising improved methods of antimicrobial application include the testing of materials for their biodegradability or for their potential to adhere to mucosal surfaces. It is concluded that the potential exists for antimicrobials applied directly to the site of intended action to contribute significantly to dental health, particularly when employed as components of practical oral hygiene regimes.