The Catholic Message Board

If there's any clergy in this website I'd like to hear their opinion

scenario:

Someone approaches holy communion in sin with enough knowledge, and on top of that he then mistreats the host with contempt and malice (dolus) while consuming it, and has sufficient conscience in the moment that he is doing wrong but does not stop. And has foreknowledge that those actions could lead to canonical penalties.

Could this subject incurr in automatic excommunication?

I see a canon prescribing latae sententiae excommunication for throwing away the sacred species or taking them away for a sacrilegious purpose (canon 1367), but that does not fit the situation you describe, and laws that carry penalties are to be interpreted strictly. I cannot find a canon that would apply here, so no, I don't think the person in question would be excommunicated latae sententiae.