The dish combines the four main tastes of Thai cuisine: sour lime, hot chile, salty fish sauce, and sweetness added by palm sugar. In Thailand, it is customary that a customer ask the preparer to make the dish suited to his or her tastes, but traditionally, a typical som tam will contain some or all of the following items:

• Chili (Lao: ພິກ, Isan: พิก, IPA: pʰik, IPA: pʰrik)
• Sugar (sometimes also palm sugar
• Garlic (Lao: ພະກເທິຍມ, paktʰiːam, Isan: กะเทียม, IPA: gaʔtʰiːam, Thai: กระเทียม, IPA: graʔtʰiːam)
• Lime (Lao: ມະນາວ, Thai/Isan: มะนาว, IPA: maʔnaːw)
• Fish sauce (Lao: ນ້ຳປາ, IPA: nam paː, Thai: น้ำปลา, IPA: nam plaː)
• Brined crabs (Lao: ປູດອງ, Isan: ปูดอง, IPA: pudɔŋ, Thai: ปูเค็ม, IPA: puɗem). These are not marine crabs, but local salted black crabs found in the flooded ricefields and canals. Isaan people eat the entire crab, including the shell.
• Shrimp paste (Lao: ກະປີ, Thai/Isan: กะปิ, IPA: gaʔpiː)
• Padaek (Lao: ປາແດກ, Isan: ปาแดก, IPA: paːdɛːk, Thai: ปลาร้า, IPA: paːraː)
• Yardlong beans (Lao: ໝາກຖ່ັວ, Isan: หมากถั่ว, IPA: maːktʰua, Thai: ถั่วฝักยาว, IPA: tʰuafakyaːw)
• Tomatoes (Lao: ໝາກເລ່ນ, Isan: หมากเลน, IPA: maːk leːn, Thai: มะเขือเทศ, IPA: maʔkʰɯːatʰeːt)
• Hog Plums (่Lao: ມະກອກ, Thai/Isan: มะกอก, maʔgɔːk)

Isan people also refer to tomatoes as เขอเคอ (IPA: kʰɤːkʰɤː) and, although rare, may refer to gai yang as ไก่ปิ้ง, pronounced the same as Lao ປິງໄກ່.

Som tam is often served with sticky rice (Lao: ເຂົ້າໜຽວ, Thai/Isan: ข้าวเหนียว, IPA: kʰaːw nio) and gai yang (Lao: ປິງໄກ່, IPA: piŋ gɑj, Isan: ไก่ย่าง, gɑj ɲːaŋ, Thai: ไก่ย่าง, IPA: gɑj jːaŋ). It is also sometimes served over rice noodles and raw vegetables to mitigate the spiciness of the dish, or simply as a snack by itself with crispy pork rinds.