Di Bona D, Magistà S, Masciopinto L, et al. - Researchers undertook this retrospective review to evaluate the rate of side effects (SE) to subcutaneous immunotherapy (SCIT) as well as treatment compliance at a hospital medically supervised facility. Participants were patients with allergic rhino-conjunctivitis with or without asthma, who were treated with SCIT to mites and pollens from 1988 to 2018. There were 2,200 patients (50.2% males; mean age 29.4 ± 11.7 years) who took 3,037 SCIT courses. Overall 957 patients (43.5%) were found to be compliant as they completed the minimally necessary treatment span of 3 years. A total of 42 anaphylactic reactions (in 29 patients) were documented; two of these were severe. There occurred no anaphylactic shock. SCIT discontinuation due to SE was reported in only 39 patients (1.8%); most of whom (24; 61.5%) were attributable to systemic reactions (urticaria, asthma, anaphylaxis). The factors that were independently related to SE were: female gender, number of vaccines delivered (2 vaccine vs 1 vaccine) and year of SCIT inception (1996–2018 vs 1988–1995). Findings revealed the safety as well as the good tolerability of SCIT, although SCIT was not absolutely free of risk. There is still scope for improvement of treatment compliance.