###### Abstract
For almost a century, sodium hypochlorite (NaOCI) has been the irrigant of choice in disinfecting root canals [12] and predominates other types of solutions available on the market for this purpose. NaOCI has been regarded as the gold standard irrigation solution for root canal treatment, mainly due to its capability to dissolve the pulpal tissue, good antimicrobial activity and ability to remove the biofilm and other organic components following mechanical instrumentation [13]. A concentration between 2 and 2.5% has been advocated, citing its antimicrobial efficacy against Streptococcus sp., _Enterococcus faecalis_ and _Actinomyces israelii_ as well as eliminating Gram-negative bacteria endotoxins [6; 14]. Despite their excellent antimicrobial activity, clinicians have voiced their concern regarding the usage of NaOCI as a root canal irrigant, especially at high concentrations. This is owing to the fact that NaOCI itself is a bleaching agent, which can cause corrosive damage to the endodontic instruments and soft tissue ulceration and necrosis [15]. In addition, several case reports have described severe outcomes following NaOCI accidents during root canal treatment, which include pain, facial oedema and swelling, oro-pharynx ulceration, dyspnoea and respiratory distress [16; 17; 18]. Further, alternating irrigation between NaOCI and chlorexidine gluconate, another antimicrobial solution can lead to the formation of a brown precipitate which may contain para-chloroeniline, a byproduct with mutagenicity potential [19]. Following the controversy surrounding the use of NaOCI in endodontics, researchers have been exploring other potential alternative irrigation solutions. They have turned their attention to developing irrigants based on the extracts of natural products since these extracts are considered cheap, readily available and, most importantly, safe [20]. Additionally, the use of natural products provides a plenteous source of bioactive molecules that can be beneficial in endodontic treatment. Extracts of neon, aloe vera, garlic, miswak and propolis are among those that have been investigated with comparable antibacterial action to those exhibited by NaOCI [21; 22]. Another natural-based product that has caught our attention is effective ecoproduce (EEP). EEP, an organic solution produced following the fermentation of fruit and vegetable organic waste, was first introduced by Dr [PERSON] in Thailand [23; 24]. It is also commonly known as garbage enzyme [25] or eco enzyme [26], although the word 'enzyme' might be inappropriate since the solution also contains organic acids and other secondary metabolites as well [27]. EEP has been used both in the agricultural and waste-management industry, mainly as a pesticide, insecticide, fertiliser, water treatment and sludge management [24; 28; 29]. Further, it also has been used as an alternative to bleaching agents for household disinfection and cleaning solutions [30]. In dentistry, in vitro studies have shown that EEP fermented for 3 and 6 months exhibits good antibacterial and antibiofilm action against _Enterococcus faecalis_, a resistant bacterial strain which is usually associated with root canal reinfection [25; 26; 27]. Additionally, [PERSON] has reported a comparable antibiofilm action of EEP fermented for 6 months with NaOCl at a 6.25% concentration [31], highlighting the potential usage of EEP as an alternative irrigation solution for root canal treatment. Despite this promising application, the biocompatibility of EEP, particularly in endodontic practice, has not been thoroughly investigated yet. This missing link should be addressed accordingly in order to produce a safe, biocompatible and highly effective root canal irrigant. Thus, we have conducted this in vitro study with the aim of evaluating the cytotoxic effects of EEP at different concentrations and fermentation periods towards pre-osteoblast cells.