The study of materials and constructive systems for the conservation and preservation of architectural heritage is of great relevance in the case of the Royal Alcazar of Seville, a World Heritage Site since 1987. This palatial complex stands out for its plasterwork decorations and this work aims to study the most significant anomaly: the detachment of all the pineapples presented on the sebka surfaces. The present study focused on the organoleptic inspection of pineapples, together with a planimetric survey and the study of their environmental conditions. The study developed has allowed (i) to establish the hypothesis of the different fixation systems used over time; (ii) to identify anomalies present in decorative pineapples; and (iii) to analyse recent emergency actions undertaken in the pineapples to prevent their detachment. The results obtained represent novel information of historical, artistic, and constructive interest in these ornamental pieces in plaster, useful for future conservation and restoration interventions.