Cholesterol, a yellowish fat-like substance, is implicated in the clogging of arteries, which can lead to heart attacks.

Bengali People have perfected the art of making various sweet dishes with the yellowish viscous fluidic substance obtained from a ripe palm fruit.

After dripping down, the snake's venom would then collect in the bottom of the pot and congeal into a yellowish gumlike substance.

It all depends upon what the "yellowish substance" is.

It is described as a yellowish brown amorphous substance.

Many brownish or yellowish substances have gradual onset of absorption in the UV.

I would guess it was introduced in that yellowish substance on the floor.

His face and throat were covered by, and his mouth choked with, a yellowish substance shot with purple.

Earwax, also known as cerumen, is a yellowish, waxy substance secreted in the ear canals.