It is, of course, no regular drink.
Warning: the following article contains spoilers for 'House of the Dragon' episode 4
'House of the Dragon' episode 4 offers a slew of new political headaches for the Targaryen family that emerged due to Rhaenyra and Daemon enjoying a sneaky night out in a brothel.
Naturally, the night out has put Rhaenyra in a compromising position. Despite the fact that she and Daemon did not hook up (although they were dangerously close to it), her virtue has falled under question. Because of that, Rhaenyra had to agree with her father's choice of a person she is now to marry: Laenor Velaryon.
But that is not an end of her troubles. While never sleeping with Daemon, she did have sex with Sir Criston Cole, therefore losing her virginity to him and potentially getting pregnant. Now that her father, King Viserys, sent her a special "tea" that is apparently a Westerosi version of Plan B, Rhaenyra faces a certain dilemma.
The tea can "rid" her of any "unwanted consequences" of her night out, but Rhaenyra does not seem to be overly enthusiastic to drink it. We never see her downing the drink, which could easily mean that she decides not to "rid" of the "consequences" at all.
According to fans, this could all be a test from Viserys.
"idk, I am still wondering if he is testing her. If she doesn't drink it, she's taking a chance of mothering a bastard. If she does, she is admitting guilt." - /StarWight_TTV
Other people even doubt that it was the King who sent the tea to Rhaenyra in the first place. After all, wasn't it Otto Hightower who reported Rhaenyra to Viserys?
"Yeah, I was pretty sure it came from Otto. Viserys doesn’t seem like he would cast doubt on Rhaenyra, especially after Alicent told him Rhaenyra swore to her. He respects both of them enough to give Rhaenyra the benefit of the doubt. Whereas Otto, despite having his own title as Hand revoked, still knows that Aegon is likely to hold the throne eventually and doesn’t want him to have another Targaryen heir to contend with. He’s seen how that plays out with Daemon and Viserys already. Once you add how little we know of his full cunning and his influence with the maesters, it almost has to be him." - /-felwinter-
We will only know for sure next Sunday, when yet another episode of 'House of the Dragon' premieres on HBO Max.