Zhoug is a Yemeni chili condiment often made with fresh herbs, garlic and spices. Green versions commonly include cilantro; red and other regional versions also exist. It is served with breads and savory dishes or used to add heat and freshness.
It is different from harissa and from shatta. Ingredient proportions, texture and heat vary, so taste before using it as a substitute for another chili sauce.
Reference: Further reading.