Haematoxylin and Eosin (H&E) staining is an essential technique used for the microscopic visualization of cytohistological structures. This method commonly applies Harris haematoxylin (HH) to stain basophilic structures, particularly cell nuclei. Generally, a regressive staining protocol is employed, which includes hydrochloric alcohol as a differentiator to remove excess stain. Alternatively, a progressive protocol can be used, which does not require differentiation, making it typically faster and less resource-intensive. This study aimed to determine the most efficient method for HH staining in H&E by comparing both regressive and progressive approaches. Thirty-two non-neoplastic human tissue samples were stained using the regressive protocol, as well as three variations of the progressive protocol with HH incubation times of 3, 4, and 5 minutes. Two specialists assessed the following parameters using a weighted scoring scale from 0 to 100 points: a) morphological preservation, b) intensity of nuclear staining, c) intensity of cytoplasmic staining, d) nuclear detail, and e) non-specific staining. The average scores were 94.06 ± 8.32 for the regressive protocol and 89.84 ± 10.00, 93.12 ± 8.27, and 92.13 ± 7.04 for the progressive protocols with incubation times of 3, 4, and 5 minutes, respectively. To evaluate the impact of the different protocols on staining quality, a one-way analysis of variance (ANOVA) was performed, revealing no significant differences (F(3, 124) = 1.463, p = 0.228); Tukey's post-hoc test supported this finding. These results suggest that the choice of protocol does not significantly affect staining quality, implying that other factors may contribute to variability in performance. Notably, the 3-minute progressive protocol emerged as the most efficient option, as it reduced staining time and eliminated the need for a differentiating agent while achieving results comparable to those of the regressive method. Future research should explore additional factors influencing staining quality, such as haematoxylin oxidation, and consider replicating the study with a more diverse sample set, including neoplastic tissues.