Background: A hordeolum is a common, painful inflammation of the eyelid margin that is usually caused by a bacterial infection. The infection affects oil glands of the eyelid and can be either internal or external. In many cases, the lesion drains spontaneously and resolves without treatment; however, the inflammation can spread to other ocular glands or tissues, and recurrences are common. If unresolved, an acute internal hordeolum can become chronic, or can develop into a chalazion. External hordeola, also known as styes, were not included in the scope of this review. Objectives: The objective of this review was to investigate the effectiveness, and when possible, the safety, of non-surgical treatments for acute internal hordeola compared with observation or placebo. Search methods: We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register (2016; Issue 12)), MEDLINE Ovid, MEDLINE Ovid Epub Ahead of Print, MEDLINE Ovid In-Process & Other Non-Indexed Citations, MEDLINE(R) Ovid Daily (January 1946 to December 2016), Embase (January 1947 to December 2016), PubMed (1948 to December 2016), Latin American and Caribbean Literature on Health Sciences (LILACS (January 1982 to December 2016)), the metaRegister of Controlled Trials (mRCT; www.controlled-trials.com (last searched 26 July 2012)), ClinicalTrials.gov (www.clinicaltrials.gov), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We used no date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 2 December 2016. Selection criteria: The selection criteria for this review included randomized or quasi-randomized clinical trials of participants diagnosed with an acute internal hordeolum. Studies of participants with external hordeola (styes), chronic hordeola, or chalazia were excluded. Non-surgical interventions of interest included the use of hot or warm compresses, lid scrubs, antibiotics, or steroids compared with observation, placebo, or other active interventions. Data collection and analysis: Two review authors independently assessed the references identified by electronic searches for inclusion in this review. No relevant studies were found. The reasons for exclusion were documented. Main results: No trials were identified for this review. Most of the references identified through our search reported on external hordeola or chronic internal hordeola. The few references specific to acute internal hordeola reported recommendations for treatment, were reports of interventional case series, case studies, or other types of observational study designs, and were published more than 20 years ago. Authors' conclusions: We did not find any evidence for or against the effectiveness of non-surgical interventions for the treatment of an internal hordeolum. Controlled clinical trials would be useful to determine which interventions are effective for the treatment of acute internal hordeola.