Sixteen lactating Egyptian buffaloes randomly assigned to a 4×4 Latin square design to investigate the effects of eucalyptus oil naturally protected in the form of leaves (EUL) or mature seed capsules (EUS) or unprotected crude oil (EUO). The control group (G1) got the basal diet consisting of concentrate feed mixture (CFM), fresh berseem (FB), rice straw (RS), and corn silage (CS) to be 40:60 concentrate: roughage ratio. In the G2, G3, and G4 animals fed the basal diet with a supplement of 200 g/head/day of EUL, EUS, or 4 ml EUO, respectively. Supplement of EUL or EUS increased NH₃-N, SCFA's, and acetic acid concentrations in-vitro than EUO. While C2/C3 ratio decreased (P<0.05) with supplement EUL or EUS compared to EUO or control diet. The total bacteria count, and cellulolytic bacteria increased (P<0.05) with supplement EUL or EUS, compared to EUO. While protozoa count increased with supplement EUO compared with EUL, EUS, or control. Methane production and degradability of NDF were lower (P<0.05) with the supplementation of EUS, EUL, or EUO compared to the control diet. Milk fat decreased (P<0.05) with EUO-supplement than the control diet, while an adverse trend was shown for lactose. No differences were found for feed conversion among EUS, EUL, or EUO. Total protein and albumin increased (P<0.05) with supplement EUL or EUS compared to EUO. Supplement EUO increased (P<0.05) AST, ALT, glucose, and creatinine. Blood urea increased (P<0.05) with feeding EUL or EUS compared to EUO, but no difference when compared to the control group. The supplementation of EUL, EUS, or EUO decreased (P<0.05) DM, OM, and CP digestibility compared to the control diet. Digestibility of EE with EUL, EUS, or EUO was higher (P<0.05) than the control diet, while it was higher (P<0.05) with supplementing EUL or EUS than supplementing EUO to the diet. Digestibility of NDF and ADF decreased (P<0.05) with supplement EUL, EUS, or EUO compared to the control diet. Feeding EUS increased (P<0.05) digestibility of NDF and ADF compared to EUL supplementation, which was increased (P<0.05) than feeding EUO. Feeding EUS increased values of TDN and DCP compared to EUL, which was higher than EUO. Finally, the results of the current study confirm that the effect of a supplement of EUO naturally protected in the form of leaves or seeds mitigates the negative effects of directly supplementing crude eucalyptus oil.