Based on the prevalence of asymptomatic kidney stones (5% in our general ward, in accordance with the literature) the value of abdominal ultrasonography in the clinical assessment of a suspected kidney-colic is discussed. The eminent importance of the stone-analysis is emphasized. In addition, the most common causes of kidney stone formation (low urine output, mechanical urinary obstruction in the renal pelvis, hypercalciuria, hyperoxaluria, insufficient urinary citric acid excretion, hyperuricosuria) are highlighted. The cardinal symptom of the urolithiasis is the presence of micro/macrohematuria (which is often absent - according to citations - in 20-80%!). Moreover, the differential diagnosis of acute flank pain, as neoplastic- or infectious diseases, reno-vascular and extrarenal causes (retro-peritoneal and mesenteric vascular processes and rupture of abdominal aneurysms), gynecological problems (e.g. rotation/rupture of ovarian cysts, ectopic pregnancy), appendicitis, diverticulitis, and splenic abscess/infarction, as well as hepato-pancreaticobiliary causes are discussed. Moreover, metabolic syndromes, e.g. the intermittant porphyria or infectious diseases (e.g, Fitz-Hugh-Curtis syndrome) and other rare pathologies (such as the «Mediterranean fever») may be at the origin of acute flank pains. A particular attention is given to possible diagnostic procedures in a primary care setting: in addition to medical history, clinical status and specific laboratory findings the value of diagnostic ultrasound, with special reference to the color-Doppler application, as the «twinkling artefact» from kidney stones and the «urinary-jet phenomenon» for the assessment of urinary outflow obstruction, is emphasized. In this context we point out that a lack of dilatation of the kidney pelvis never excludes a kidney-colic, on the other hand, a dilatation of the kidney pelvis does not necessarily mean congestion! The conservative treatment strategies (avoidance of excessive drinking - an obstructed kidney protects itself - NSAID in combination with Tamsulosin, especially in case of prevesical urolithiasis) are discussed. The critical stone size (≤5 mm) and the absence of «red flags» (especially obstructive and inflammatory signs) allow a non-specialist medical outpatient treatment of acute nephro-and ureterolithiasis. The possible complications of the urolithiasis, especially the urosepsis and the (iatrogenic) fornix rupture are highlighted, as well as the formation of a renal abscess or hydronephrosis. A short look is given to the metaphylaxis of the urolithiasis and its «recurrence rate».