He lists, "I took this decongestant  and then I took this nasal spray," and then all of a sudden a lightbulb goes off and he says, "Oh! You should never mix this  decongestant with this nasal spray.
"Tomé un descongestionante y me apliqué un espray nasal". Y entonces, de repente, se enciende el bombillo: "¡Ah! Nunca se debe mezclar este descongestionante y este espray nasal.