Toothache plant leaves are broadly ovate to triangular, measuring 2-4 inches (5-11 cm) in length and 2-3 inches (4-8 cm) in width. They have a truncate or shortly attenuate base, with margins that are toothed and an acute to shortly acuminate apex. The leaves are generally glabrous, meaning they lack significant hair or fuzz, and present a smooth texture on both surfaces. These characteristics are essential for identification.

The flowers of toothache plant are comprised of numerous small, yellow to orange disc florets, each approximately 1/10 of an inch (2.54 mm) long. These florets form dense, spherical clusters atop slender stems. They exhibit a bright, warm hue that draws attention, making them a vibrant addition to any garden. Blooming occurs through the summer and fall, providing extended periods of visual interest. The flowers typically lack a notable scent, focusing their appeal on visual characteristics.

The stem of toothache plant is typically decumbent or erect, featuring a noticeable reddish hue. It is hairless and smooth, presenting a glabrous texture. The stems may vary in thickness but are generally slender, supporting the plant well either when sprawling across the ground or growing vertically. Branching is common and can occur along the stem, contributing to its supportive structure. In both prostrate and upright positions, the stems of toothache plant are a distinctive identifying feature due to their color and appearance.

The fruit of toothache plant is a small, black achene, measuring about 0.08-0.1 inches (2-2.5 mm) in length. These achenes contain the plant's seeds and are the product of the disc florets, which are yellow to orange in color and measure approximately 0.11-0.13 inches (2.7-3.3 mm) in length. A key characteristic of the fruit is its size and black color, which contrasts with the vibrant disc florets. The achenes typically have a dry, smooth texture, and their small size might require a magnifying tool for detailed examination.