Citral (OO), a component of orange oils, has bacteriostatic and bactericidal properties against isolated mastitis pathogen Escherichia coli P4 at relatively low concentrations that do not interfere with the cow’s cellular immune response in vitro. The objective of this study was to evaluate the effectiveness of OO as an intramammary therapy for experimentally induced E. coli mastitis. One rear quarter from 18 healthy, multiparous mid-lactation dairy cows was inoculated with ~800 cfu of E. coli P4. Infections were established in all inoculated quarters. One of 3 intramammary treatments were administered into the infected quarter at 24 h post-infection for 4 consecutive days (6 cows/treatment). Treatments were 1% vol/vol OO twice daily, ceftiofur hydrochloride once daily, and sterile phosphate buffer solution twice daily. Foremilk from the infected quarter was aseptically sampled twice daily before milking (0700 and 1600 h) and coccygeal blood was sampled once daily through d 7 post inoculation and weekly through d 35 post inoculation. Health examinations were performed before blood sampling, and milk production and feed intake were recorded daily. Results were analyzed by ANOVA using the MIXED procedure of SAS 9.4 with treatment, time and treatment by time interaction declared as fixed effects and cow declared as a random effect. Milk E. coli cfu/mL was log10 transformed and not affected by treatment or treatment across time (P > 0.05). Treatments did not affect peak bacteria concentrations in milk (P > 0.05). Somatic cell count (P = 0.03) differed across time by treatment as OO lowered somatic cell count on d 2.5 and 3.5 following inoculation as compared with the antibiotic and control treatments. Somatic cell score, clinical score, health parameters, total daily milk production and daily dry matter intake were not affected by treatment or treatment across time (P > 0.05). In summary, OO did not alter production parameters or health of E. coli mastitis-induced cows; however, the anti-inflammatory effects of OO may be useful to reduce the severity of the infection.